How to interpolate when we have two different sizes

Hi everyone,

Someone would be kind enough to help me how to do an interpolation when we have two different sizes being A and B.

I will do interpolation A and B then concatenate the result as follows interpolation_A_B= [interpolation_A, interpolation_B].

Here is my code:

%% Data

A=[0,-2.24489741646952,-4.62733420618208,-6.95719767650665,-9.01707651070867,-10.6031942911103,-11.5925433634751,-11.8888513183929,-11.4910074241661,-10.3269616567176,-8.37131286980876,-5.73036557765802,-2.73380439351284,0.0658350852258175,2.24268430772633,3.60945691919934,4.23841606693665,4.38617345954930,4.33237937220543,4.24478638091837,4.11981257851839,3.91272625898743,3.64047136322393,3.40598831808841,3.35826429186336,3.50296413009803,3.66772774367983,3.56377296314676,2.91695995975226,1.61068736575304];

temps_A=[10,56,103,149,196,242,289,335,382,428,475,521,568,614,661,707,754,800,847,893,940,986,1033,1079,1126,1172,1219,1265,1312,1358];

B=[0,0.266260173065289,-0.0707528123775336,-1.10727656343698,-2.67932011084229,-4.49683089873686,-6.28901889839069,-7.86823684856092,-9.10292224756012,-9.93528552429639,-10.3943919840282,-10.6200553018127,-10.6751851242251,-10.4946119723262,-9.93187689931717,-8.79370001488421,-7.21878022731030,-5.48155200603622,-3.92374944116942,-2.83303212357369,-2.34292583956979,-2.31255526161581,-2.51444122441427,-2.69362744473124,-2.68977697021639,-2.43432161929766,-1.93071631270870,-1.25144435000955,-0.517481281517809,-1.93071631270870,-1.25144435000955,-0.517481281517809];

temps_B=[10,41,72,104,135,166,198,229,260,292,323,354,386,417,448,480,511,542,574,605,636,668,699,731,762,793,825,856,887,918,949,980,1011];

%% interpolation A

time_interpolation_A=min(temps_A):1:max(temps_A);

A_interpolation = interp1(temps_A,A,time_interpolation_A);

%% interpolation B

time_interpolation_B=min(temps_B):1:max(temps_B);

B_interpolation = interp1(temps_B,B,time_interpolation_B);

%% concatenate interpolation A & B

Interpolation_A_B=[A_interpolation,B_interpolation];

Answer 1

[Star Strider]

A=[0,-2.24489741646952,-4.62733420618208,-6.95719767650665,-9.01707651070867,-10.6031942911103,-11.5925433634751,-11.8888513183929,-11.4910074241661,-10.3269616567176,-8.37131286980876,-5.73036557765802,-2.73380439351284,0.0658350852258175,2.24268430772633,3.60945691919934,4.23841606693665,4.38617345954930,4.33237937220543,4.24478638091837,4.11981257851839,3.91272625898743,3.64047136322393,3.40598831808841,3.35826429186336,3.50296413009803,3.66772774367983,3.56377296314676,2.91695995975226,1.61068736575304];
temps_A=[10,56,103,149,196,242,289,335,382,428,475,521,568,614,661,707,754,800,847,893,940,986,1033,1079,1126,1172,1219,1265,1312,1358];
B=[0,0.266260173065289,-0.0707528123775336,-1.10727656343698,-2.67932011084229,-4.49683089873686,-6.28901889839069,-7.86823684856092,-9.10292224756012,-9.93528552429639,-10.3943919840282,-10.6200553018127,-10.6751851242251,-10.4946119723262,-9.93187689931717,-8.79370001488421,-7.21878022731030,-5.48155200603622,-3.92374944116942,-2.83303212357369,-2.34292583956979,-2.31255526161581,-2.51444122441427,-2.69362744473124,-2.68977697021639,-2.43432161929766,-1.93071631270870,-1.25144435000955,-0.517481281517809,-1.93071631270870,-1.25144435000955,-0.517481281517809];
temps_B=[10,41,72,104,135,166,198,229,260,292,323,354,386,417,448,480,511,542,574,605,636,668,699,731,762,793,825,856,887,918,949,980];

Data = [size(A); size(B)]

Data = 2×2

1 30 1 32

Create new temperature vectors from the existing vectors, and interpolate.

NewLength = 50;
NewAt = linspace(min(temps_A), max(temps_A), NewLength);
Anew = interp1(temps_A, A, NewAt)

Anew = 1×50

0 -1.3426 -2.7021 -4.0966 -5.4904 -6.8838 -8.0994 -9.2437 -10.1922 -10.9314 -11.5105 -11.7446 -11.8455 -11.6126 -11.1584 -10.4623 -9.4048 -8.2178 -6.6384 -4.9848 -3.2308 -1.5340 0.1225 1.3967 2.5174 3.3348 3.8539 4.2220 4.3228 4.3773

NewBt = linspace(min(temps_B), max(temps_B), NewLength);
Bnew = interp1(temps_B, B, NewBt)

Bnew = 1×50

0 0.1700 0.1729 -0.0424 -0.6274 -1.3598 -2.3637 -3.4750 -4.6294 -5.7381 -6.7964 -7.8048 -8.6071 -9.2940 -9.8089 -10.1565 -10.4216 -10.5657 -10.6413 -10.6745 -10.5592 -10.3364 -9.9771 -9.3163 -8.5345 -7.5288 -6.4514 -5.3603 -4.3967 -3.5690

figure
plot(temps_A, A, '.-b')
hold on
plot(NewAt, Anew, '.r')
hold off
grid
legend('Original', 'Interpolated', 'Location','best')
title('A')

figure
plot(temps_B, B, '.-b')
hold on
plot(NewBt, Bnew, '.r')
hold off
grid
legend('Original', 'Interpolated', 'Location','best')
title('B')
legend('Original', 'Interpolated', 'Location','best')

.

[Crocola Cool]

His ok, but why did you remove the 1, it was sampling at 1: time_interpolation_A=min(temps_A):1:max(temps_A);

I just want to understand

[Star Strider]

Because that turned out not to be accurate or appropriate for these data.

This way is better.

[Crocola Cool]

Thank you very much #Strider for sharing your knowledge and I am grateful.

See you soon

[Star Strider]

As always, my pleasure!

Answer 2

[J Chen]

temps_B and B have different size. They need to be the same size.

[Crocola Cool]

# Hi J Chen

yes I was mistaken, here is the modified code.

When concatenating, I would like to have interpolation A in column and the same for interpolation B.

clear all

clc

A=[0,-2.24489741646952,-4.62733420618208,-6.95719767650665,-9.01707651070867,-10.6031942911103,-11.5925433634751,-11.8888513183929,-11.4910074241661,-10.3269616567176,-8.37131286980876,-5.73036557765802,-2.73380439351284,0.0658350852258175,2.24268430772633,3.60945691919934,4.23841606693665,4.38617345954930,4.33237937220543,4.24478638091837,4.11981257851839,3.91272625898743,3.64047136322393,3.40598831808841,3.35826429186336,3.50296413009803,3.66772774367983,3.56377296314676,2.91695995975226,1.61068736575304];

temps_A=[10,56,103,149,196,242,289,335,382,428,475,521,568,614,661,707,754,800,847,893,940,986,1033,1079,1126,1172,1219,1265,1312,1358];

B=[0,0.266260173065289,-0.0707528123775336,-1.10727656343698,-2.67932011084229,-4.49683089873686,-6.28901889839069,-7.86823684856092,-9.10292224756012,-9.93528552429639,-10.3943919840282,-10.6200553018127,-10.6751851242251,-10.4946119723262,-9.93187689931717,-8.79370001488421,-7.21878022731030,-5.48155200603622,-3.92374944116942,-2.83303212357369,-2.34292583956979,-2.31255526161581,-2.51444122441427,-2.69362744473124,-2.68977697021639,-2.43432161929766,-1.93071631270870,-1.25144435000955,-0.517481281517809,-1.93071631270870,-1.25144435000955,-0.517481281517809];

temps_B=[10,41,72,104,135,166,198,229,260,292,323,354,386,417,448,480,511,542,574,605,636,668,699,731,762,793,825,856,887,918,949,980];

time_interpolation_A=min(temps_A):1:max(temps_A);

A_interpolation = interp1(temps_A,A,time_interpolation_A);

time_interpolation_B=min(temps_B):1:max(temps_B);

B_interpolation = interp1(temps_B,B,time_interpolation_B);

Interpolation_A_B=[A_interpolation',B_interpolation'];