Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.


dpb
Posts:
9,242
Registered:
6/7/07


Re: Subscript indices must either be real positive integers or logicals Error + Code
Posted:
Feb 20, 2013 5:56 PM


On 2/20/2013 11:24 AM, Jerome wrote: > was wondering if someone can explain to me what this error means. And, > if possible, how to resolve it? ??? Subscript indices must either be > real positive integers or logicals.
Pretty much exactly what it saysMatlab arrays are 1based so all indices have to start at (at least) one ("real positive integers" part) or be logical indices which are an array of T,F that select the subset within the array on that logic basis rather than by absolute position.
> Error in ==> interp2>linear at 344 > F = ( arg3(ndx).*(onemt) + arg3(ndx+1).*t ).*(1s) + ... > > Error in ==> interp2 at 220 > zi = linear(ExtrapVal,x,y,z,xi,yi); > > Error in ==> snake at 71 > ssx = gamma*xs  kappa*interp2(fx,xs,ys); > > This is my complete code: > ...
> eext = (double(wl.*eline) + double(we.*eedge wt) .* eterm); %eext as a > weighted sum of eline, eedge and eterm > > [fx, fy] = gradient(eext); %computing the gradient ...
Somehow you've passed an illegal set of inputs to interp2() that has caused it to error. You can tell this by tracing back the errors to the initiating call. I don't have time at present to try to delve deeply into your code but the threeargument form of the call to interp2 assumes the V (fx) here is a set of function values that match 1:M and 1:N for the size of the array in the two dimension. I'm suspecting this probably isn't so is the root cause that confused interp2.
Study
doc interp2
and the examples carefully to see where it went wrong.




