{"record":{"id":"4e410cefd627d582","repo":"Yalantis/uCrop","slug":"cimg-appname-math-parser-cimg-s-s-s-t-4e410c","errorCode":null,"errorMessage":"[\" cimg_appname \"_math_parser] CImg<%s>::%s: %s: Type of second arguments ('%s') does not match with fourth argument 'nb_channelsP=%u', in expression '%s'.","messagePattern":"\\[\" cimg_appname \"_math_parser\\] CImg<(.+?)>::(.+?): (.+?): Type of second arguments \\('(.+?)'\\) does not match with fourth argument 'nb_channelsP=%u', in expression '(.+?)'\\.","errorType":"exception","errorClass":"CImgArgumentException","httpStatus":null,"severity":"error","filePath":"ucrop/src/main/jni/CImg.h","lineNumber":22550,"sourceCode":"\n            if (!std::strncmp(ss,\"mul(\",4)) { // Matrix multiplication\n              _cimg_mp_op(\"Function 'mul()'\");\n              s1 = ss4; while (s1<se1 && (*s1!=',' || level[s1 - expr._data]!=clevel1)) ++s1;\n              arg1 = compile(ss4,s1,depth1,0,block_flags);\n              s2 = ++s1; while (s2<se1 && (*s2!=',' || level[s2 - expr._data]!=clevel1)) ++s2;\n              arg2 = compile(s1,s2,depth1,0,block_flags);\n              arg3 = s2<se1?compile(++s2,se1,depth1,0,block_flags):1;\n              _cimg_mp_check_type(arg1,1,2,0);\n              _cimg_mp_check_type(arg2,2,2,0);\n              _cimg_mp_check_const_scalar(arg3,3,3);\n              p1 = size(arg1);\n              p2 = size(arg2);\n              p3 = (unsigned int)mem[arg3];\n              arg5 = p2/p3;\n              arg4 = p1/arg5;\n              if (arg4*arg5!=p1 || arg5*p3!=p2) {\n                _cimg_mp_strerr;\n                throw CImgArgumentException(\"[\" cimg_appname \"_math_parser] \"\n                                            \"CImg<%s>::%s: %s: Types of first and second arguments ('%s' and '%s') \"\n                                            \"do not match with third argument 'nb_colsB=%u', \"\n                                            \"in expression '%s'.\",\n                                            pixel_type(),_cimg_mp_calling_function,s_op,\n                                            s_type(arg1)._data,s_type(arg2)._data,p3,s0);\n              }\n              pos = vector(arg4*p3);\n              CImg<ulongT>::vector((ulongT)mp_matrix_mul,pos,arg1,arg2,arg4,arg5,p3).move_to(code);\n              return_comp = true;\n              _cimg_mp_return(pos);\n            }\n\n            if (!std::strncmp(ss,\"mirror(\",7)) { // Mirror image\n              _cimg_mp_op(\"Function 'mirror()'\");\n              s1 = ss7; while (s1<se1 && (*s1!=',' || level[s1 - expr._data]!=clevel1)) ++s1;\n              arg1 = compile(ss7,s1,depth1,0,block_flags);\n              s2 = ++s1; while (s2<se1 && (*s2!=',' || level[s2 - expr._data]!=clevel1)) ++s2;\n              arg2 = compile(s1,s2,depth1,0,block_flags);","sourceCodeStart":22532,"sourceCodeEnd":22568,"githubUrl":"https://github.com/Yalantis/uCrop/blob/f788b534b48c144edf786c8cddbf0e029e637804/ucrop/src/main/jni/CImg.h#L22532-L22568","documentation":"In the CImg math parser, an operator (e.g. a matrix multiplication-style op) requires the first argument's element count to factor exactly as rows*nb_colsB where nb_colsB is the third argument, and the second argument to factor nb_colsB*cols. When p1 is not divisible as required (arg4*arg5!=p1 || arg5*p3!=p2), the parser throws this CImgArgumentException because the matrix dimensions of the two operands are incompatible for the operation.","triggerScenarios":"Using a math-parser operator that multiplies/combines two vectors as matrices when the declared column counts (nb_colsB) do not divide the operand sizes: e.g. calling an expression like 'mprod(A,B,nb_colsB)' where size(A) is not divisible by nb_colsB or size(B) is not nb_colsB*k.","commonSituations":"Hand-written G'MIC/CImg formulas with wrong column-count constants, vectors reshaped from images whose channel count changed, or copy-pasted expressions between differently sized images.","solutions":["Check that size of argument1 divided by nb_colsP yields an integer and size of argument2 equals nb_colsP*k","Print the actual vector sizes with a debug expression (e.g. print(size(#ind)) or 'l' the vector geometry) before the failing op","Adjust the column-count argument or resize/reshape one operand with 'resize()' / 'unroll()' so dimensions match","Use the correct operator if a plain elementwise op (e.g. '*' not matrix product) was intended"],"exampleFix":"// before (size(A)=6, nb_colsB=4 -> 6 not divisible by 4)\nmprod(A,B,4)\n// after\nmprod(A,B,3) // 6 = 2*3, and size(B)=3*k","handlingStrategy":"validation","validationCode":"// G'MIC/CImg expression-level guard before using mprod-like op:\n// ensure size(A) % cols == 0 and size(B) == cols * rowsB\nif size(A)%cols!=0 || size(B)%cols!=0\n  error \"operand sizes incompatible with nb_colsB=\"cols\nfi","typeGuard":null,"tryCatchPattern":"try { run(expr) } catch (CImgArgumentException &e) { std::cerr << \"dim mismatch: \" << e.what(); }","preventionTips":["Verify divisibility of operand sizes by the column-count constant","Print vector geometries with size()/print() during development","Keep matrix column counts as named variables, not magic numbers"],"tags":["cimg","math-parser","dimension-mismatch"],"backgroundTag":"tensor-shape-mismatch","analyzedSha":"f788b534b48c144edf786c8cddbf0e029e637804","analyzedAt":"2026-09-08T08:36:04.887Z","contentChangedAt":"2026-09-08T08:36:04.887Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}