MATLAB: Would I be getting “NaN” from a matrix I entered

griddata

Hey all,

I seem to be getting a "NaN" from a matrix I entered as a variable while using the function griddata. Is there any obvious reason for this? Possibly difficulty interpolating a value?

Best Answer

We need to see your code. My guess is that you’re asking it to extrapolate.

Related Solutions

MATLAB: How can this probability function be entered

You have to vectorise your assignment for ‘P’:

k = 1.3806488E-23;
e = 6.0217657E-19;
z = 2;
Vh = 1E-3;
T1 = 25+273.15;
T2 = 37+273.15;
V = linspace(-0.1, 0.09);
VV = V-Vh;
P = 1./(1+exp(-z*e*(VV/(k*T1))));
figure(1)
plot(V, P)
grid

See Matrix vs Array Operations for details.

MATLAB: How to fix error about interp1

One way (without seeing your data, so this is a guess on my part):

y85 = find(y <= 85, 1, 'last');
yi = interp1(y(y85-1:y85+1),x(y85-1:y85+1),xi, 'linear','extrap');

That is how I would do it. This assumes there is only 1 where ‘y’ is approximately 85.

Note — This is obviously UNTESTED CODE. It should work, if there is one ‘y’ near 85.

EDIT — Added the 'extrap' option to make my approach more robust.

Best Answer

Related Solutions

MATLAB: How can this probability function be entered

MATLAB: How to fix error about interp1

Related Question