1 | /* |
---|
2 | * INT_HIST(x, n) is a histogram of all integer values 1..n in x. |
---|
3 | * If n is not given, max(x) is used. |
---|
4 | */ |
---|
5 | #include "mex.h" |
---|
6 | #include "util.h" |
---|
7 | |
---|
8 | void mexFunction(int nlhs, mxArray *plhs[], |
---|
9 | int nrhs, const mxArray *prhs[]) |
---|
10 | { |
---|
11 | int rows, cols, len, i, bins; |
---|
12 | double *indata, *outdata; |
---|
13 | |
---|
14 | if((nrhs < 1) || (nrhs > 2)) |
---|
15 | mexErrMsgTxt("Usage: h = int_hist(x, n)"); |
---|
16 | |
---|
17 | /* prhs[0] is first argument. |
---|
18 | * mxGetPr returns double* (data, col-major) |
---|
19 | * mxGetM returns int (rows) |
---|
20 | * mxGetN returns int (cols) |
---|
21 | */ |
---|
22 | rows = mxGetM(prhs[0]); |
---|
23 | cols = mxGetN(prhs[0]); |
---|
24 | indata = mxGetPr(prhs[0]); |
---|
25 | len = rows*cols; |
---|
26 | |
---|
27 | if(mxIsSparse(prhs[0])) |
---|
28 | mexErrMsgTxt("Cannot handle sparse matrices. Sorry."); |
---|
29 | |
---|
30 | if(nrhs == 2) bins = *mxGetPr(prhs[1]); |
---|
31 | else { |
---|
32 | bins = indata[0]; |
---|
33 | for(i=0;i<len;i++) { |
---|
34 | if(indata[i] > bins) bins = indata[i]; |
---|
35 | } |
---|
36 | } |
---|
37 | |
---|
38 | /* plhs[0] is first output */ |
---|
39 | plhs[0] = mxCreateDoubleMatrix(1, bins, mxREAL); |
---|
40 | outdata = mxGetPr(plhs[0]); |
---|
41 | |
---|
42 | for(i=0;i<len;i++) { |
---|
43 | int v = (int)(*indata++) - 1; |
---|
44 | if((v < 0) || (v >= bins)) |
---|
45 | mexErrMsgTxt("value out of bounds"); |
---|
46 | outdata[v]++; |
---|
47 | } |
---|
48 | } |
---|
49 | |
---|