mex2 Inputs and Outputs

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1. 新建normalizecolsmx.c文件

/* normalizecolsmx.c Normalize the columns of a matrixSyntax: B = normalizecols(A)or B = normalizecols(A,p)The columns of matrix A are normalized so that norm(B(:,n),p) = 1. */#include <math.h>#include "mex.h"#define IS_REAL_2D_FULL_DOUBLE(P) (!mxIsComplex(P) && mxGetNumberOfDimensions(P) == 2 && !mxIsSparse(P) && mxIsDouble(P))#define IS_REAL_SCALAR(R) (IS_REAL_2D_FULL_DOUBLE(P) && mxGetNumberOfElements(P) == 1)void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]){#define B_OUTplhs[0]#define A_INprhs[0]#define P_INprhs[1]double *B, *A, p, colnorm;int M, N, m, n;if( nrhs < 1 || nrhs > 2)mexErrMsgTxt("Wrong number of input arguments.");else if(nlhs > 1)mexErrMsgTxt("Too many output arguements");if( !IS_REAL_2D_FULL_DOUBLE(A_IN) )mexErrMsgTxt("A must be a real 2D full double array.");if( nrhs == 1)p = 2.0;elsep = mxGetScalar(P_IN);M = mxGetM(A_IN);N = mxGetN(A_IN);A = mxGetPr(A_IN);B_OUT = mxCreateDoubleMatrix(M, N, mxREAL);B = mxGetPr(B_OUT);for(n = 0; n < N; n++){for(m = 0, colnorm = 0.0; m < M; m++)colnorm += pow(A[m + M*n], p);colnorm = pow( fabs(colnorm), 1.0/p);for(m = 0; m < M; m++)B[m + M * n] = A[m + M * n]/colnorm;}return ;}

2. 编译normalizecolsmx.c 文件

mex normalizecolsmx.c

3. 新建normalizecols.m文件,在此文件使用c文件编译出来的mexw64文件

%normalizecols.mfunction B = normalizecols(A, p)    if nargin < 2        if nargin < 1            error('Not enough input arguements');        end        p = 2;    end        if ~isreal(A) || ndims(A) ~= 2 || issparse(A) || ~isa(A, 'double')        error('A must be a real 2D full double array.');    elseif ~ isreal(p) || ~isa(p, 'double') || numel(p) ~= 1        error('P must be a real double scalar.');    end        B = normalizecolsmx(A, p);end

4. 在命令行中使用normalizecols.m, 输入

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