请问这样拟合e指数曲线问题在哪里？

1. x = 400:0.4:1000;
2. y = pop3;
3. f = fittype('a*exp(-x/b+c)','independent','x','coefficients',{'a','b','c'});
4. x1 = x';
5. y1 = y';
6. ff = fit(x1,y1,f);
7. xi = x;
8. yi = ff(xi);
9. figure
10. plot(xi,yi,'b-',x,y,'g*');

2.24876E-5

2.24673E-5

2.2447E-5

2.24264E-5

2.24067E-5

2.23863E-5

2.23665E-5

2.23463E-5

2.23262E-5

2.23065E-5

2.22863E-5

2.22669E-5

2.22475E-5

2.22287E-5

2.22102E-5

2.21918E-5

2.21743E-5

2.21568E-5

2.21399E-5

2.21231E-5

2.21068E-5

2.20909E-5

2.20749E-5

2.20596E-5

2.20443E-5

2.20297E-5

2.20148E-5

2.20001E-5

2.19859E-5

2.19715E-5

2.19575E-5

2.19433E-5

2.19297E-5

2.19161E-5

2.19024E-5

2.18892E-5

2.18761E-5

2.18634E-5

2.18503E-5

2.18378E-5

2.18257E-5

2.18133E-5

2.18013E-5

2.17894E-5

2.1778E-5

2.17664E-5

2.1755E-5

2.17442E-5

2.17333E-5

2.17227E-5

2.17121E-5

2.1702E-5

2.1692E-5

2.16816E-5

2.16719E-5

2.1662E-5

2.16522E-5

2.16423E-5

2.16326E-5

2.16233E-5

2.16135E-5

2.16039E-5

2.15945E-5

2.15852E-5

2.15756E-5

2.15661E-5

2.15571E-5

2.15476E-5

2.15385E-5

2.15296E-5

2.1521E-5

2.15123E-5

2.15036E-5

2.14954E-5

2.14871E-5

2.14787E-5

2.14701E-5

2.14619E-5

2.14535E-5

2.14447E-5

2.14364E-5

2.14281E-5

2.14196E-5

2.14111E-5

2.14027E-5

2.13944E-5

2.13858E-5

2.13773E-5

2.13689E-5

2.13607E-5

2.13522E-5

2.13438E-5

2.1336E-5

2.13275E-5

2.13195E-5

2.13117E-5

2.13037E-5

2.1296E-5

2.1288E-5

2.12805E-5

2.12729E-5

2.12653E-5

2.12577E-5

2.12506E-5

2.12433E-5

2.12356E-5

2.12289E-5

2.12213E-5

2.1214E-5

2.12069E-5

2.11992E-5

2.11918E-5

2.1184E-5

2.11759E-5

2.11681E-5

2.11601E-5

2.11516E-5

2.11439E-5

2.11358E-5

2.11273E-5

2.11195E-5

2.11112E-5

2.11027E-5

2.10948E-5

2.10863E-5

2.10778E-5

2.10696E-5

2.10605E-5

2.10519E-5

2.10432E-5

2.10336E-5

2.10247E-5

2.10154E-5

2.10056E-5

2.09962E-5

2.09866E-5

2.09768E-5

2.09672E-5

2.09577E-5

2.0948E-5

2.09389E-5

2.09294E-5

2.09201E-5

2.09109E-5

2.09015E-5

2.08923E-5

2.08831E-5

2.08738E-5

2.08647E-5

2.08557E-5

2.08467E-5

2.08378E-5

2.08289E-5

2.08202E-5

2.08114E-5

2.08026E-5

2.07939E-5

2.07851E-5

2.07765E-5

2.07677E-5

2.07588E-5

2.07502E-5

2.07412E-5

2.07324E-5

2.07235E-5

2.07144E-5

2.07054E-5

2.06961E-5

2.06866E-5

2.06771E-5

2.06672E-5

2.06573E-5

2.06472E-5

2.0637E-5

2.06269E-5

2.06166E-5

2.06065E-5

2.05963E-5

2.05861E-5

2.0576E-5

2.05656E-5

2.05555E-5

2.05452E-5

2.05349E-5

2.05246E-5

2.05139E-5

2.05031E-5

2.04921E-5

2.04808E-5

2.04695E-5

2.04577E-5

2.0446E-5

2.04342E-5

2.04222E-5

2.04106E-5

2.03987E-5

2.03872E-5

2.03759E-5

2.03646E-5

2.03537E-5

2.03429E-5

2.03322E-5

2.03216E-5

2.03112E-5

2.03007E-5

2.02902E-5

2.02797E-5

2.02694E-5

2.02586E-5

2.02481E-5

2.02375E-5

2.02263E-5

2.02155E-5

2.02042E-5

2.01929E-5

2.01817E-5

2.01702E-5

2.01588E-5

2.01472E-5

2.01357E-5

2.0124E-5

2.01122E-5

2.01004E-5

2.00885E-5

2.00763E-5

2.00643E-5

2.00519E-5

2.00393E-5

2.00271E-5

2.00141E-5

2.00015E-5

1.99889E-5

1.99755E-5

1.99626E-5

1.9949E-5

1.99353E-5

1.99213E-5

1.99068E-5

1.98923E-5

1.98771E-5

1.98619E-5

1.98466E-5

1.98305E-5

1.9815E-5

1.97992E-5

1.97828E-5

1.97672E-5

1.97511E-5

1.97345E-5

1.97188E-5

1.97022E-5

1.96858E-5

1.96696E-5

1.96528E-5

1.96365E-5

1.96196E-5

1.96027E-5

1.9586E-5

1.95684E-5

1.95514E-5

1.95341E-5

1.95161E-5

1.94992E-5

1.94812E-5

1.94634E-5

1.94461E-5

1.94275E-5

1.94099E-5

1.93918E-5

1.93731E-5

1.93552E-5

1.93364E-5

1.93175E-5

1.92991E-5

1.92796E-5

1.92607E-5

1.92416E-5

1.92218E-5

1.92032E-5

1.91834E-5

1.91642E-5

1.91454E-5

1.91251E-5

1.91064E-5

1.90864E-5

1.90662E-5

1.90469E-5

1.90258E-5

1.90056E-5

1.89852E-5

1.89639E-5

1.89434E-5

1.89221E-5

1.89008E-5

1.88796E-5

1.8858E-5

1.88365E-5

1.88149E-5

1.87931E-5

1.87717E-5

1.87499E-5

1.87282E-5

1.8707E-5

1.86852E-5

1.86639E-5

1.86427E-5

1.86212E-5

1.86002E-5

1.85791E-5

1.8558E-5

1.85369E-5

1.85161E-5

1.84949E-5

1.84736E-5

1.84531E-5

1.84314E-5

1.84102E-5

1.83894E-5

1.83675E-5

1.83464E-5

1.8325E-5

1.83035E-5

1.82823E-5

1.82604E-5

1.82395E-5

1.82177E-5

1.81959E-5

1.81751E-5

1.81531E-5

1.81318E-5

1.81107E-5

1.8089E-5

1.80679E-5

1.80465E-5

1.80253E-5

1.80039E-5

1.79826E-5

1.79615E-5

1.794E-5

1.79185E-5

1.78968E-5

1.78752E-5

1.78527E-5

1.78305E-5

1.78084E-5

1.77848E-5

1.77627E-5

1.77395E-5

1.77162E-5

1.7694E-5

1.767E-5

1.76476E-5

1.76248E-5

1.7601E-5

1.75796E-5

1.75565E-5

1.75341E-5

1.75135E-5

1.74909E-5

1.74702E-5

1.74499E-5

1.74284E-5

1.74088E-5

1.73884E-5

1.73681E-5

1.7349E-5

1.73289E-5

1.73094E-5

1.7291E-5

1.72709E-5

1.72523E-5

1.7234E-5

1.72141E-5

1.71964E-5

1.71775E-5

1.71584E-5

1.7141E-5

1.71219E-5

1.7104E-5

1.70865E-5

1.70678E-5

1.70506E-5

1.7033E-5

1.70149E-5

1.69982E-5

1.69805E-5

1.69631E-5

1.69468E-5

1.69291E-5

1.69127E-5

1.68964E-5

1.68792E-5

1.68637E-5

1.6847E-5

1.6831E-5

1.68152E-5

1.67987E-5

1.67833E-5

1.6767E-5

1.67512E-5

1.67354E-5

1.67195E-5

1.6704E-5

1.6688E-5

1.66729E-5

1.66572E-5

1.66422E-5

1.66273E-5

1.6612E-5

1.65981E-5

1.6583E-5

1.65693E-5

1.65554E-5

1.65413E-5

1.65285E-5

1.65144E-5

1.65018E-5

1.64886E-5

1.64754E-5

1.64631E-5

1.64499E-5

1.64378E-5

1.64251E-5

1.64127E-5

1.64009E-5

1.63884E-5

1.63769E-5

1.63649E-5

1.63534E-5

1.6342E-5

1.63305E-5

1.63195E-5

1.63082E-5

1.62974E-5

1.62865E-5

1.62759E-5

1.62655E-5

1.6255E-5

1.62451E-5

1.62349E-5

1.62252E-5

1.62154E-5

1.62058E-5

1.61965E-5

1.6187E-5

1.61781E-5

1.61689E-5

1.61602E-5

1.61516E-5

1.61429E-5

1.61348E-5

1.61265E-5

1.61187E-5

1.61109E-5

1.61032E-5

1.60958E-5

1.60884E-5

1.60813E-5

1.60742E-5

1.60674E-5

1.60606E-5

1.6054E-5

1.60476E-5

1.60411E-5

1.6035E-5

1.60284E-5

1.60223E-5

1.6016E-5

1.60096E-5

1.60036E-5

1.59969E-5

1.59909E-5

1.59844E-5

1.59781E-5

1.59719E-5

1.59652E-5

1.59592E-5

1.59526E-5

1.59463E-5

1.594E-5

1.59335E-5

1.59275E-5

1.59211E-5

1.5915E-5

1.5909E-5

1.59028E-5

1.5897E-5

1.5891E-5

1.58852E-5

1.58794E-5

1.58735E-5

1.5868E-5

1.58623E-5

1.58567E-5

1.58512E-5

1.58456E-5

1.58403E-5

1.58348E-5

1.58293E-5

1.5824E-5

1.58185E-5

1.58132E-5

1.58079E-5

1.58025E-5

1.57974E-5

1.57922E-5

1.57872E-5

1.57821E-5

1.57772E-5

1.57724E-5

1.57676E-5

1.5763E-5

1.57583E-5

1.57538E-5

1.57493E-5

1.57448E-5

1.57404E-5

1.57361E-5

1.57317E-5

1.57273E-5

1.57229E-5

1.57184E-5

1.57139E-5

1.57092E-5

1.57045E-5

1.56999E-5

1.5695E-5

1.56903E-5

1.56855E-5

1.56807E-5

1.5676E-5

1.56711E-5

1.56663E-5

1.56615E-5

1.56566E-5

1.56519E-5

1.5647E-5

1.56424E-5

1.56377E-5

1.56331E-5

1.56286E-5

1.56241E-5

1.56198E-5

1.56153E-5

1.5611E-5

1.56067E-5

1.56023E-5

1.55979E-5

1.55936E-5

1.55892E-5

1.55848E-5

1.55804E-5

1.5576E-5

1.55717E-5

1.55673E-5

1.55629E-5

1.55586E-5

1.55542E-5

1.55498E-5

1.55454E-5

1.5541E-5

1.55366E-5

1.55323E-5

1.55279E-5

1.55236E-5

1.55193E-5

1.55151E-5

1.5511E-5

1.55067E-5

1.55027E-5

1.54984E-5

1.54943E-5

1.54901E-5

1.54858E-5

1.54816E-5

1.54772E-5

1.54728E-5

1.54682E-5

1.54636E-5

1.54589E-5

1.54541E-5

1.54492E-5

1.54442E-5

1.54392E-5

1.54342E-5

1.54292E-5

1.54242E-5

1.54192E-5

1.54143E-5

1.54094E-5

1.54045E-5

1.53996E-5

1.53948E-5

1.53899E-5

1.53851E-5

1.53803E-5

1.53755E-5

1.53707E-5

1.53659E-5

1.53609E-5

1.53561E-5

1.53511E-5

1.53461E-5

1.5341E-5

1.53358E-5

1.53306E-5

1.53251E-5

1.53198E-5

1.53143E-5

1.53088E-5

1.53033E-5

1.52976E-5

1.52921E-5

1.52862E-5

1.52807E-5

1.52748E-5

1.5269E-5

1.52632E-5

1.52572E-5

1.52514E-5

1.52454E-5

1.52394E-5

1.52333E-5

1.52272E-5

1.52211E-5

1.52148E-5

1.52085E-5

1.5202E-5

1.51955E-5

1.51889E-5

1.51822E-5

1.51754E-5

1.51685E-5

1.51614E-5

1.51542E-5

1.51469E-5

1.51395E-5

1.51321E-5

1.51244E-5

1.51169E-5

1.51091E-5

1.51014E-5

1.50936E-5

1.50857E-5

1.50779E-5

1.50698E-5

1.50618E-5

1.50536E-5

1.50453E-5

1.5037E-5

1.50284E-5

1.50199E-5

1.50112E-5

1.50024E-5

1.49936E-5

1.49844E-5

1.49756E-5

1.49662E-5

1.4957E-5

1.49476E-5

1.49378E-5

1.49285E-5

1.49184E-5

1.49089E-5

1.48987E-5

1.48886E-5

1.48788E-5

1.48681E-5

1.48583E-5

1.48474E-5

1.48371E-5

1.48266E-5

1.48155E-5

1.48053E-5

1.47938E-5

1.47834E-5

1.47722E-5

1.47611E-5

1.47504E-5

1.47386E-5

1.47281E-5

1.47163E-5

1.47052E-5

1.46941E-5

1.46822E-5

1.46715E-5

1.46595E-5

1.46485E-5

1.4637E-5

1.46253E-5

1.46144E-5

1.46024E-5

1.45914E-5

1.45798E-5

1.45683E-5

1.45571E-5

1.45453E-5

1.45343E-5

1.45227E-5

1.45114E-5

1.45002E-5

1.44887E-5

1.44776E-5

1.44663E-5

1.44551E-5

1.44438E-5

1.44324E-5

1.44211E-5

1.44097E-5

1.43983E-5

1.43869E-5

1.43755E-5

1.43641E-5

1.43527E-5

1.43413E-5

1.43299E-5

1.43185E-5

1.43071E-5

1.42957E-5

1.42843E-5

1.42728E-5

1.42613E-5

1.42497E-5

1.42381E-5

1.42266E-5

1.42146E-5

1.4203E-5

1.4191E-5

1.41791E-5

1.41673E-5

1.41551E-5

1.41435E-5

1.41315E-5

1.41197E-5

1.4108E-5

1.40961E-5

1.40847E-5

1.4073E-5

1.40617E-5

1.40504E-5

1.40391E-5

1.40281E-5

1.40168E-5

1.4006E-5

1.39949E-5

1.3984E-5

1.39731E-5

1.39619E-5

1.3951E-5

1.39397E-5

1.39286E-5

1.39174E-5

1.39061E-5

1.3895E-5

1.38836E-5

1.38724E-5

1.3861E-5

1.38497E-5

1.38384E-5

1.38269E-5

1.38156E-5

1.3804E-5

1.37927E-5

1.37811E-5

1.37697E-5

1.37583E-5

1.37467E-5

1.37356E-5

1.3724E-5

1.37126E-5

1.37013E-5

1.36896E-5

1.36785E-5

1.36668E-5

1.36554E-5

1.3644E-5

1.36323E-5

1.36211E-5

1.36093E-5

1.35979E-5

1.35863E-5

1.35745E-5

1.3563E-5

1.3551E-5

1.35393E-5

1.35274E-5

1.35153E-5

1.35036E-5

1.34915E-5

1.34797E-5

1.34679E-5

1.3456E-5

1.34444E-5

1.34325E-5

1.3421E-5

1.34095E-5

1.33977E-5

1.33863E-5

1.33746E-5

1.33631E-5

1.33517E-5

1.33399E-5

1.33287E-5

1.3317E-5

1.33055E-5

1.32941E-5

1.32824E-5

1.3271E-5

1.32592E-5

1.32478E-5

1.32362E-5

1.32246E-5

1.32133E-5

1.32018E-5

1.31908E-5

1.31796E-5

1.31688E-5

1.31584E-5

1.31477E-5

1.31376E-5

1.31273E-5

1.31173E-5

1.31074E-5

1.30975E-5

1.30881E-5

1.30784E-5

1.30693E-5

1.30601E-5

1.30511E-5

1.30424E-5

1.30335E-5

1.30252E-5

1.30167E-5

1.30084E-5

1.30002E-5

1.29919E-5

1.29839E-5

1.29757E-5

1.29678E-5

1.29598E-5

1.29519E-5

1.29442E-5

1.29364E-5

1.29289E-5

1.29214E-5

1.29141E-5

1.29067E-5

1.28997E-5

1.28928E-5

1.28858E-5

1.28795E-5

1.28728E-5

1.28666E-5

1.28604E-5

1.28543E-5

1.28486E-5

1.28424E-5

1.28371E-5

1.28313E-5

1.28257E-5

1.28204E-5

1.28148E-5

1.28097E-5

1.2804E-5

1.2799E-5

1.27936E-5

1.27883E-5

1.27835E-5

1.27782E-5

1.27736E-5

1.27685E-5

1.27639E-5

1.27593E-5

1.27544E-5

1.27504E-5

1.27456E-5

1.27415E-5

1.27372E-5

1.27329E-5

1.27289E-5

1.27245E-5

1.27206E-5

1.27163E-5

1.27122E-5

1.27082E-5

1.2704E-5

1.27001E-5

1.26958E-5

1.26918E-5

1.26875E-5

1.26832E-5

1.2679E-5

1.26746E-5

1.26704E-5

1.2666E-5

1.26618E-5

1.26574E-5

1.26531E-5

1.26489E-5

1.26446E-5

1.26405E-5

1.26363E-5

1.26323E-5

1.26283E-5

1.26243E-5

1.26205E-5

1.26166E-5

1.26129E-5

1.26091E-5

1.26053E-5

1.26017E-5

1.25979E-5

1.25943E-5

1.25906E-5

1.25869E-5

1.25831E-5

1.25793E-5

1.25756E-5

1.25718E-5

1.25681E-5

1.25642E-5

1.25605E-5

1.25568E-5

1.2553E-5

1.25493E-5

1.25456E-5

1.2542E-5

1.25384E-5

1.25349E-5

1.25315E-5

1.25281E-5

1.25248E-5

1.25216E-5

1.25184E-5

1.25152E-5

1.25121E-5

1.25089E-5

1.25057E-5

1.25026E-5

1.24994E-5

1.24962E-5

1.24929E-5

1.24897E-5

1.24865E-5

1.24832E-5

1.24801E-5

1.24769E-5

1.24736E-5

1.24704E-5

1.2467E-5

1.24637E-5

1.24603E-5

1.24571E-5

1.24537E-5

1.24504E-5

1.2447E-5

1.24437E-5

1.24404E-5

1.24371E-5

1.24337E-5

1.24303E-5

1.24269E-5

1.24234E-5

1.24199E-5

1.24165E-5

1.2413E-5

1.24096E-5

1.24062E-5

1.24028E-5

1.23994E-5

1.23959E-5

1.23925E-5

1.23889E-5

1.23854E-5

1.23818E-5

1.23783E-5

1.23748E-5

1.23713E-5

1.2368E-5

1.23645E-5

1.23612E-5

1.23578E-5

1.23544E-5

1.2351E-5

1.23475E-5

1.23442E-5

1.23407E-5

1.23374E-5

1.2334E-5

1.23306E-5

1.23272E-5

1.23237E-5

1.23203E-5

1.23168E-5

1.23133E-5

1.23098E-5

1.23062E-5

1.23027E-5

1.22991E-5

1.22956E-5

1.2292E-5

1.22884E-5

1.22847E-5

1.2281E-5

1.22773E-5

1.22735E-5

1.22699E-5

1.22661E-5

1.22624E-5

1.22586E-5

1.22546E-5

1.22507E-5

1.22465E-5

1.22424E-5

1.22381E-5

1.22338E-5

1.22295E-5

1.22251E-5

1.22208E-5

1.22162E-5

1.22117E-5

1.2207E-5

1.22022E-5

1.21975E-5

1.21925E-5

1.21878E-5

1.21828E-5

1.2178E-5

1.21731E-5

1.21681E-5

1.21633E-5

1.21582E-5

1.21533E-5

1.21481E-5

1.2143E-5

1.21379E-5

1.21326E-5

1.21275E-5

1.21221E-5

1.21168E-5

1.21115E-5

1.2106E-5

1.21007E-5

1.20951E-5

1.20896E-5

1.2084E-5

1.20783E-5

1.20725E-5

1.20666E-5

1.20606E-5

1.20545E-5

1.20484E-5

1.20423E-5

1.20361E-5

1.203E-5

1.20239E-5

1.20178E-5

1.20118E-5

1.20057E-5

1.19996E-5

1.19933E-5

1.1987E-5

1.19806E-5

1.1974E-5

1.19674E-5

1.19607E-5

1.19539E-5

1.19471E-5

1.19402E-5

1.19333E-5

1.19262E-5

1.19191E-5

1.19118E-5

1.19045E-5

1.18971E-5

1.18896E-5

1.18821E-5

1.18747E-5

1.18672E-5

1.18597E-5

1.18523E-5

1.18446E-5

1.18372E-5

1.18296E-5

1.1822E-5

1.18145E-5

1.18069E-5

1.17994E-5

1.17918E-5

1.17843E-5

1.17768E-5

1.17691E-5

1.17618E-5

1.1754E-5

1.17465E-5

1.1739E-5

1.17312E-5

1.1724E-5

1.17161E-5

1.17088E-5

1.17012E-5

1.16935E-5

1.16863E-5

1.16782E-5

1.1671E-5

1.16633E-5

1.16556E-5

1.16485E-5

1.16406E-5

1.16335E-5

1.16258E-5

1.16183E-5

1.1611E-5

1.16032E-5

1.15961E-5

1.15884E-5

1.1581E-5

1.15737E-5

1.1566E-5

1.15588E-5

1.15512E-5

1.15438E-5

1.15362E-5

1.15286E-5

1.15211E-5

1.15133E-5

1.15058E-5

1.1498E-5

1.14903E-5

1.14826E-5

1.14748E-5

1.14672E-5

1.14594E-5

1.14517E-5

1.1444E-5

1.14364E-5

1.14288E-5

1.14213E-5

1.14139E-5

1.14065E-5

1.13993E-5

1.13919E-5

1.13849E-5

1.13777E-5

1.13706E-5

1.13636E-5

1.13566E-5

1.13495E-5

1.13426E-5

1.13357E-5

1.13285E-5

1.13217E-5

1.13146E-5

1.13073E-5

1.13004E-5

1.12928E-5

1.12857E-5

1.12783E-5

1.12709E-5

1.12635E-5

1.1256E-5

1.12488E-5

1.12411E-5

1.12339E-5

1.12263E-5

1.12187E-5

1.12115E-5

1.12036E-5

1.11963E-5

1.11886E-5

1.1181E-5

1.11735E-5

1.11656E-5

1.1158E-5

1.11501E-5

1.11422E-5

1.11344E-5

1.11264E-5

1.11185E-5

1.11106E-5

1.11027E-5

1.10949E-5

1.10871E-5

1.10792E-5

1.10716E-5

1.10638E-5

1.1056E-5

1.10483E-5

1.10405E-5

1.10327E-5

1.10251E-5

1.10173E-5

1.10096E-5

1.10019E-5

1.0994E-5

1.09861E-5

1.09783E-5

1.09702E-5

1.09621E-5

1.0954E-5

1.09457E-5

1.09375E-5

1.09291E-5

1.09207E-5

1.09123E-5

1.09035E-5

1.08951E-5

1.08862E-5

1.08773E-5

1.08686E-5

1.08593E-5

1.08504E-5

1.08412E-5

1.08317E-5

1.08227E-5

1.08132E-5

1.08039E-5

1.07948E-5

1.07854E-5

1.07762E-5

1.07671E-5

1.0758E-5

1.07489E-5

1.07402E-5

1.07312E-5

1.07225E-5

1.07142E-5

1.07054E-5

1.06973E-5

1.06892E-5

1.06809E-5

1.06734E-5

1.06654E-5

1.06579E-5

1.06507E-5

1.06434E-5

1.06366E-5

1.06297E-5

1.06232E-5

1.06167E-5

1.06106E-5

1.06045E-5

1.05984E-5

1.05928E-5

1.05868E-5

1.05812E-5

1.05756E-5

1.05699E-5

1.05646E-5

1.05589E-5

1.05536E-5

1.05482E-5

1.05427E-5

1.05375E-5

1.05322E-5

1.05269E-5

1.05216E-5

1.05165E-5

1.05113E-5

1.05063E-5

1.05013E-5

1.04961E-5

1.04915E-5

1.04863E-5

1.04815E-5

1.04768E-5

1.04717E-5

1.04672E-5

1.04623E-5

1.04576E-5

1.0453E-5

1.04483E-5

1.04438E-5

1.04393E-5

1.04349E-5

1.04304E-5

1.04262E-5

1.04218E-5

1.04175E-5

1.04134E-5

1.0409E-5

1.04051E-5

1.04008E-5

1.03968E-5

1.03928E-5

1.03886E-5

1.03848E-5

1.03807E-5

1.03768E-5

1.0373E-5

1.03692E-5

1.03655E-5

1.03618E-5

1.03583E-5

1.03548E-5

1.03514E-5

1.03481E-5

1.03447E-5

1.03415E-5

1.03382E-5

1.0335E-5

1.03317E-5

1.03285E-5

1.03252E-5

1.03219E-5

1.03186E-5

1.03152E-5

1.0312E-5

1.03085E-5

1.03053E-5

1.0302E-5

1.02986E-5

1.02955E-5

1.02921E-5

1.02889E-5

1.02857E-5

1.02824E-5

1.02793E-5

1.0276E-5

1.02728E-5

1.02696E-5

1.02663E-5

1.0263E-5

1.02597E-5

1.02561E-5

1.02527E-5

1.02491E-5

1.02455E-5

1.02419E-5

1.02382E-5

1.02345E-5

1.02308E-5

1.0227E-5

1.02233E-5

1.02196E-5

1.02159E-5

1.02122E-5

1.02087E-5

1.02051E-5

1.02016E-5

1.01982E-5

1.01947E-5

1.01915E-5

1.01881E-5

1.01849E-5

1.01816E-5

1.01783E-5

1.01752E-5

1.01719E-5

1.01688E-5

1.01655E-5

1.01623E-5

1.01591E-5

1.01559E-5

1.01528E-5

1.01495E-5

1.01464E-5

1.01432E-5

1.01401E-5

1.0137E-5

1.01339E-5

1.01308E-5

1.01277E-5

1.01246E-5

1.01215E-5

1.01185E-5

1.01154E-5

1.01123E-5

1.01092E-5

1.01061E-5

1.0103E-5

1.00998E-5

1.00967E-5

1.00934E-5

1.00902E-5

1.00868E-5

1.00834E-5

1.00801E-5

1.00766E-5

1.00731E-5

1.00696E-5

1.0066E-5

1.00624E-5

1.00588E-5

1.00551E-5

1.00514E-5

1.00477E-5

1.00439E-5

1.00402E-5

1.00364E-5

1.00328E-5

1.0029E-5

1.00252E-5

1.00215E-5

1.00177E-5

1.0014E-5

1.00102E-5

1.00065E-5

1.00028E-5

9.99916E-6

9.9955E-6

9.99188E-6

9.98828E-6

9.98467E-6

9.98112E-6

9.97751E-6

9.97397E-6

9.97039E-6

9.9668E-6

9.96327E-6

9.95962E-6

9.95607E-6

9.95241E-6

9.94874E-6

9.94509E-6

9.9413E-6

9.9376E-6

9.93377E-6

9.92996E-6

9.92614E-6

9.92224E-6

9.91839E-6

9.91445E-6

9.91055E-6

9.90655E-6

9.90256E-6

9.89852E-6

9.89439E-6

9.89028E-6

9.88603E-6

9.88183E-6

9.8775E-6

9.87315E-6

9.86877E-6

9.86426E-6

9.85977E-6

9.85515E-6

9.85053E-6

9.8458E-6

9.84106E-6

9.83626E-6

9.83142E-6

9.82653E-6

9.82162E-6

9.81667E-6

9.81167E-6

9.80674E-6

9.80162E-6

9.79669E-6

9.79155E-6

9.78651E-6

9.7815E-6

9.77627E-6

9.77143E-6

9.76619E-6

9.76127E-6

9.75621E-6

9.75112E-6

9.7462E-6

9.741E-6

9.73611E-6

9.7309E-6

9.72594E-6

9.72075E-6

9.71571E-6

9.71058E-6

9.70533E-6

9.70043E-6

9.69496E-6

9.69013E-6

9.68474E-6

9.67964E-6

9.67459E-6

9.66908E-6

9.66434E-6

9.65876E-6

9.65387E-6

9.64867E-6

9.64338E-6

9.63853E-6

9.63306E-6

9.62825E-6

9.62291E-6

9.61788E-6

9.61278E-6

9.60755E-6

9.60256E-6

9.59717E-6

9.59227E-6

9.58677E-6

9.5817E-6

9.57644E-6

9.57091E-6

9.56595E-6

9.56016E-6

9.55507E-6

9.54956E-6

9.54391E-6

9.53884E-6

9.53291E-6

9.52769E-6

我想用已有数据x,y拟合出一个形式为a*exp(-x/b+c)的e指数公式，得到其中的a, b, c三个系数

结果显示 ff = fit(x1,y1,f); 这一行错误，错误提示如下，y1向量就是列向量，为什么会出现这样的错误呢？正确的应该怎么写呢？

1. 错误使用 fit>iFit (第 139 行)
2. Y must be a column vector.
4. 出错 fit (第 116 行)
5. [fitobj, goodness, output, convmsg] = iFit( xdatain, ydatain, fittypeobj, ...
7. 出错 eee (第 22 行)
8. ff = fit(x1,y1,f);

Answer 1

[starlight Smith]

你画蛇添足了。

x = 400:0.4:1000; 它本来是行向量，所以才用 x1 = x'; 来转置成列向量。

而你的pop3本来就是列向量，y = pop3; 再 y1 = y'; 不就成了行向量了么？

改成

ff = fit( reshape( x, [], 1 ), reshape( y, [], 1 ), f )

另外你的模型也有问题，a * exp( -x / b + c ) 参数多余

a * exp( -x / b + c ) = a * exp( -x / b ) * exp( c ) = a * exp( c ) * exp( -x / b ) = ap * exp( -x / b )

你的参数a与c不独立，实际上可以写到一起去