Error using matlab.int​ernal.math​.interp1 The sample points must be finite.

when I ran a script,

for i=1:sz(2)
    tOut(:,i) = interp1(x(:,i),v(:,i),xq(:,i));     
end

I got those errors

Error using matlab.internal.math.interp1

The sample points must be finite.

Error in interp1 (line 188)

VqLite = matlab.internal.math.interp1(X,V,method,method,Xqcol);

Error in coolprop_tab.MoistAir.calcMoistHeatCool (line 782)

tOut(:,i) = interp1(x(:,i),v(:,i),xq(:,i));

[KSSV]

Attach your data x, v and xq. It seems there is a problem with the data.

[huiting wang]

here is the part of x,v and xq, I put the whole function below

%%
x  = -(mDry  .* (hDryIn - hDryOut) + ...
    mVapIn .* hVapIn - mVapOut .* hVapOut + ...
    mWatIn .* hWatIn - mWatOut .* hWatOut);
v  = FOut.t;

if isvector(Q)
    xq = Q;
else
    xq = cumsum(Q);
end

for i=1:sz(2)
    
    tOut(:,i) = interp1(x(:,i),v(:,i),xq(:,i));  
    
end
%%

%%%%%The whole function is:
function tOut = calcMoistHeatCool(mFlow,Q,HeatOrCool,varargin)
% Calculates the new temperature of a Moist Air fluid, depending on
% the amount of heating or cooling is provided.
%
%

sz = size(Q);

if nargin == 4
    FIn  = varargin{1};
    FOut = FIn.copy();
elseif nargin == 6
    pIn = varargin{1};
    tIn = varargin{2};
    X_totIn = varargin{3};
    FIn  = coolprop_tab.MoistAir('p',pIn,'t',tIn,'X_tot',X_totIn);
    FOut = FIn.copy();
end

switch lower(HeatOrCool)
    case 'heating'
        Q = abs(Q);
    case 'cooling'
        Q = -abs(Q);
end

% Save the initial enthalpy of the dry air, vapour and water
hDryIn  = FIn.h_dry_air;
hVapIn  = FIn.h_vapor;
hWatIn  = FIn.h_water;

cpDryIn = FIn.cp_dry_air;
if isvector(Q)
    tMax = FIn.t + sum(Q,2)./(mFlow * cpDryIn);
else
    tMax = FIn.t + sum(Q,1)./(mFlow * cpDryIn);
end

% Define dry air, vapour and water mass flows from total mass
% flow
XwatIn   = FIn.X_tot - FIn.Xs; XwatIn(XwatIn < 0) = 0;
mDry   = mFlow ./(1 + FIn.X + XwatIn);
mVapIn = mDry .* FIn.X;
mWatIn = mDry .* XwatIn;

% Initialise tOut
tOut = zeros(sz);

% Update FOut
k = 1000;            oi = ones(k,numel(FIn.p));
p_     = oi.*FIn.p;
X_tot_ = oi.*FIn.X_tot;
t_     = oi;
for i=1:sz(2)
    t_(:,i) = linspace(FIn.t(i),tMax(i),1000);
end

FOut.updateFluid('p',p_,'t',t_,'X_tot',X_tot_);
hDryOut  = FOut.h_dry_air;
hVapOut  = FOut.h_vapor;
hWatOut  = FOut.h_water;

XwatOut = FOut.X_tot - FOut.Xs; XwatOut(XwatOut < 0) = 0;
mVapOut = mDry .* FOut.X;
mWatOut = mDry .* XwatOut;

% Calculate the cumulative heating or cooling load
x  = -(mDry  .* (hDryIn - hDryOut) + ...
    mVapIn .* hVapIn - mVapOut .* hVapOut + ...
    mWatIn .* hWatIn - mWatOut .* hWatOut);
v  = FOut.t;

if isvector(Q)
    xq = Q;
else
    xq = cumsum(Q);
end

for i=1:sz(2)
    
    tOut(:,i) = interp1(x(:,i),v(:,i),xq(:,i));  
    
end

tOut = [FIn.t ; tOut];

end

[huiting wang]

There is something strange, my collegue use the same codes, same version of MATLAB, but he got no problem,

but when I ran the script on my computer, it just gets errors

[huiting wang]

x is a 1000*50 double, v is a 1000*50 double, and xq is a 20*50 double, the data has no problem, I use x(:,1),v(:,1) and xq(:1) to do a interp1 function call, and there is no error. But when I ran my script, it show errors again

my test is here

K>>testx = x(:,1);

K>> testv = v(:,1);

K>> testxq = xq(:,1);

K>> interp1(testx,testv,testxq)

ans =

307.6069

307.0587

306.5055

305.9470

305.3835

304.8147

304.2408

303.6617

303.0773

302.4877

301.8929

301.2928

300.6874

300.0766

299.4607

298.8394

298.2129

297.5811

296.9440

296.3017

ran my script, the error is:

Error using matlab.internal.math.interp1

The sample points must be finite.

Error in interp1 (line 188)

VqLite = matlab.internal.math.interp1(X,V,method,method,Xqcol);

Error in coolprop_tab.MoistAir.calcMoistHeatCool (line 783)

tOut(:,i) = interp1(x(:,i),v(:,i),xq(:,i));

Error in at_fdplus.evap.plate_fin.PlateFinHE/calcBlock (line 250)

t.new.cf = CF.calcMoistHeatCool(mDot_CF,Q.wall,'Cooling',CF.p(1,:),CF.t(1,:),CF.X_tot(1,:));

Error in TestPlateFinHE (line 25)

Q.AKG = HE_AKG.calcBlock(FIN_HF,FIN_CF,mDot.hf,mDot.cf);

Answer 1

[Steven Lord]

Error in coolprop_tab.MoistAir.calcMoistHeatCool (line 783)
                tOut(:,i) = interp1(x(:,i),v(:,i),xq(:,i));

Set a breakpoint on line 783 of coolprop_tab.MoistAir.calcMoistHeatCool or set an error breakpoint (which doesn't require you to specify a line number.) Then run your code. Once MATLAB stops at the breakpoint, show us what these commands return:

locationOfNonfiniteX = find(~isfinite(x(:, i)))
locationOfNonfiniteV = find(~isfinite(v(:, i)))
locationOfNonfiniteXq = find(~isfinite(xq(:, i)))

At least one of those variables should be non-empty. Look at the values of x, v, and/or xq at those locations and you should find they are either Inf or NaN. Once you've identified the problem locations, you'll need to work your way back through your code to determine where and why the nonfinite values were introduced.

Inf likely came in from an overflow; if you multiplied an extremely large number by another number the result could be greater than realmax.

NaN likely would come from dividing 0 by 0 or subtracting Inf from Inf. There are other ways that you can get a NaN but those are two of the more common.

[huiting wang]

K>> locationOfNonfiniteX = find(~isfinite(x(:, i)))

locationOfNonfiniteV = find(~isfinite(v(:, i)))

locationOfNonfiniteXq = find(~isfinite(xq(:, i)))

locationOfNonfiniteX =

0×1 empty double column vector

locationOfNonfiniteV =

0×1 empty double column vector

locationOfNonfiniteXq =

0×1 empty double column vector

[Steven Lord]

I'm guessing this code is in a loop. If so, keep running until you find the column of x, v, and/or xq that has the nonfinite data.

[huiting wang]

the call of intterp1 function is indead a for-loop,but the value of x,v,xq are already defined, all value in these three arrays are 8 doubles, the first row of x is 0, x,v,xq are not calculated in a loop

part of data:

x = [0 0 0 0 ......

-33.4436754520186 -33.6320781597295 -33.8204638769074 -34.0088325974662 .....

-66.8773808240819 -67.2540736138778 -67.6307318006384 -68.0073553721683 .....

-100.301123027146 -100.865993391092 -101.430810918744 -101.995575591848 .....

-133.714908970212 -134.467844517515 -135.220708375837 -135.973500521303 ......

........

] x is 1000*50 double

v = [308.150000000000 308.150000000000 308.150000000000 308.150000000000 308.150000000000 ....

308.132735976222 308.132638705915 308.132541444217 308.132444191131 308.132346946660 ....

308.115471952443 308.115277411830 308.115082888434 308.114888382262 308.114693893320 ....

308.098207928665 308.097916117745 308.097624332651 308.097332573393 308.097040839980 .....

308.080943904887 308.080554823660 308.080165776868 308.079776764524 308.079387786640 .....

308.063679881109 308.063193529576 308.062707221086 308.062220955655 308.061734733300 .....

308.046415857330 308.045832235491 308.045248665303 308.044665146786 308.044081679960 .....

.....] v is 1000*50 double

xq = [-1047.32884340479 -1053.22978509923 -1059.13020454832 -1065.03010155478 ....

-2094.65768680958 -2106.45957019847 -2118.26040909665 -2130.06020310956 ....

-3141.98653021437 -3159.68935529770 -3177.39061364497 -3195.09030466434 ....

-4189.31537361916 -4212.91914039693 -4236.52081819330 -4260.12040621912 ....

-5236.64421702395 -5266.14892549617 -5295.65102274162 -5325.15050777390 ....

-6283.97306042875 -6319.37871059540 -6354.78122728994 -6390.18060932868 ...

-7331.30190383354 -7372.60849569464 -7413.91143183827 -7455.21071088346 ....

....] xq is 20*50 double

I find no infinite data in them

Answer 2

[huiting wang]

I stilled don't know the reason of error, but the bug is fixed magically, I'm not sure what I did solved this problem, but thank you all guys for your valuable advice!

[凡奇]

I‘m also getting the same error, but I don't know how to solve it.......

[Bob photonics]

Use this code to look for NaN/Inf values in your matrix/array/table

~isfinite(YourMatrix)  %if it shows a logical 1 then you've a NaN/Inf value
[row, col] = find(~isfinite(YourMatrix)) % will show you all the locations where you have NaN values