Trying to use fminsearch but always says "Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 1-by-2821"

I have very simple code and works well manually and I can fit with actual data. Could you please help me with this? I stuck a week! I want to optimaize Par which includs three number. tau and Tfm_mis are measured minutes and measured data, respectively.

Any help is severly appreciated.

Function:

function [RMSE,Tfm_MLS] = MLS_fit1(par,tau,Tfm_mis)
%Tfm_MLS are our calculated data in timely basis
%Input constants
rho_s = 2533;                       %[kg/mc]
c_s = 840;                         %[J/kg.K]
eps = 0.367;
T_0 = 12;
rho_w = 1020;                       %water density [kg/mc] 
c_w = 4186;
r_bh= 0.076;                        %borehole ID/OD=151/165
q=56.53;                            %[W/m]
%equations from here and by using above data
C_0 = rho_s*c_s*(1-eps)+rho_w*c_w*eps; 

est = r_bh^2*C_0/4*tau*par(1);
f=(1./est).*exp((-1./est)-((par(2)^2)*c_w^2*r_bh^2*rho_w^2)/16*par(1));
T=cumtrapz(est,f);

f=(1./est).*exp((-1./est)-((par(2)^2)*c_w^2*r_bh^2*rho_w^2)/16*par(1));
T=cumtrapz(est,f);

dteta= 45*pi/180;
teta =(dteta : dteta : 2*pi);
z = q./(4*pi*par(1)).*exp((par(2).*rho_w.*c_w.*r_bh.*cos(teta))./2.*par(1));

g=T*z;
A=mean(g');
B = T_0+A;
Tfm_MLS= B + (q * par(3));
%Objective
%Tfm_mis are our measured data and tau are their time (minute)
RMSE = (sum((Tfm_MLS-Tfm_mis).^2)/length(tau).^0.5);
end 

script:

close all, clear all,  clc
load TRT_Grouted.txt
[min,n]=size(TRT_Grouted);
t_in=60;
t_end=2880;
tau = TRT_Grouted(t_in:t_end,1);
Tfm_mis = TRT_Grouted(t_in:t_end,2);
par=[1.5,1E-5,0.03];
options= optimset('Display', 'iter');
[par,RMSE] = fminsearch(@(par) MLS_fit1(par,tau,Tfm_mis), par, options);

[KALYAN ACHARJYA]

Please share load TRT_Grouted.txt?

[Saeid Bina]

Here you are.

Thank you in advance.

[Walter Roberson]

By the way notice you have repeated lines

f=(1./est).*exp((-1./est)-((par(2)^2)*c_w^2*r_bh^2*rho_w^2)/16*par(1));
T=cumtrapz(est,f);
f=(1./est).*exp((-1./est)-((par(2)^2)*c_w^2*r_bh^2*rho_w^2)/16*par(1));
T=cumtrapz(est,f);

[Saeid Bina]

Yes sorry for my typo mistake in coing from MATLAB.

Answer 1

[Walter Roberson]

g=T*z;

That is 2821 x 1 * 1 x 8, giving 2821 x 8.

A=mean(g');

The transpose gives 8 x 2821. The mean proceeds along the first non-singular dimension, so gives 1 x 2821.

B = T_0+A;
Tfm_MLS= B + (q * par(3));

Tfm_MLS is 1 x 2821

RMSE = (sum((Tfm_MLS-Tfm_mis).^2)/length(tau).^0.5);

Tfm_MLS is 1 x 2821. Tfm_mis (from input) is 2821 x 1. Before R2016b, subtracting those would give an error; now it gives a 2821 x 2821 result. sum() of that along one dimension gives a 1 x 2821 result, which is not what you want to be returned.

You should be using

A = mean(g, 2);

which will give a 2821 x 1 result.

However, I recommend you reconsider the mathematics more. When you take 2821 x 1 * 1 x 8 and then take the mean() along the second dimension, then the result is equivalent to 2821 x 1 * mean(1 x 8) -- that is you could skip steps by using

A = T .* mean(z,2);

where mean(z,2) would be a scalar.

[Walter Roberson]

T is our tempreture at each minute and z is each angle and I needed to multiply each minute to each 8 angle.

Then calculate the average of all angles.

That is the same as multiplying the temperatures by the average over the angles, instead of having to take the average of (temperature times angle), Taking mean(z,2) once and multiplying the temperatures by that would be much more efficient than what you are doing now.

[Saeid Bina]

https://www.mathworks.com/matlabcentral/answers/490572-trying-to-use-fminsearch-but-always-says-unable-to-perform-assignment-because-the-size-of-the-left#answer_401055

This code works now with the help of Dear Walter. Can nayone help me how can I see the tried parameters for each iteration?

I think I should use outlet function (since Fminsearch does not have that option) but I was failed always.

Answer 2

[Saeid Bina]

oh, Thank you so much. It works! I am so thankful. Juat for explaining:

T is our tempreture at each minute and z is each angle and I needed to multiply each minute to each 8 angle.

Then calculate the average of all angles.

Just one more thing that I asked before but nobody answered me, could you help me how can I see the tried parameters for each iteration?

I think I should use outlet function (since Fminsearch does not have that option) but I was failed always.

[KALYAN ACHARJYA]

Please post this message as comment (Just below the Walter's Answer). You got the answer from GEM of Matlab, please do accept the answer, if the answer helped you to solve the issue.

[Saeid Bina]

Thank you so much Dear Kalyan, I did, and I accepted Mr. Walters's answer that help me! Do I need to copy his answer again or my new question?

[KALYAN ACHARJYA]

No, just mention this link on second question(if it is related and helped to answer the question)

Be specific always? Keep Learning!

[Saeid Bina]

Thanks again. I think I am correct now.