{"record":{"id":"6967ea4be1cdf59c","repo":"Yalantis/uCrop","slug":"cimg-appname-math-parser-cimg-s-s-s-type","errorCode":null,"errorMessage":"[cimg_appname_math_parser] CImg<%s>::%s: %s: Type of first argument ('%s') does not match with second argument 'nb_colsA=%u', in expression '%s'.","messagePattern":"\\[cimg_appname_math_parser\\] CImg<(.+?)>::(.+?): (.+?): Type of first argument \\('(.+?)'\\) does not match with second argument 'nb_colsA=%u', in expression '(.+?)'\\.","errorType":"exception","errorClass":"CImgArgumentException","httpStatus":null,"severity":"error","filePath":"ucrop/src/main/jni/CImg.h","lineNumber":22229,"sourceCode":"              }\n              if (arg2!=~0U) {\n                _cimg_mp_check_const_scalar(arg2,2,3);\n                arg2 = (unsigned int)mem[arg2];\n              }\n              _cimg_mp_check_type(arg3,3,1,0);\n              _cimg_mp_check_type(arg4,4,1,0);\n\n              if (is_vector(arg1)) {\n                p1 = size(arg1);\n                if (arg2==~0U) { // nb_colsA not specified: assuming square matrix\n                  _cimg_mp_check_matrix_square(arg1,1);\n                  p2 = p3 = (unsigned int)cimg::round(std::sqrt((float)p1));\n                } else {\n                  p2 = arg2;\n                  p3 = p1/p2;\n                  if (p3*p2!=p1) {\n                    _cimg_mp_strerr;\n                    throw CImgArgumentException(\"[\" cimg_appname \"_math_parser] \"\n                                                \"CImg<%s>::%s: %s: Type of first argument ('%s') \"\n                                                \"does not match with second argument 'nb_colsA=%u', \"\n                                                \"in expression '%s'.\",\n                                                pixel_type(),_cimg_mp_calling_function,s_op,\n                                                s_type(arg1)._data,p2,s0);\n                  }\n                }\n                pos = vector(p1);\n                CImg<ulongT>::vector((ulongT)mp_matrix_invert,pos,arg1,p2,p3,arg3,arg4).move_to(code);\n                return_comp = true;\n                _cimg_mp_return(pos);\n              }\n              if (is_const_scalar(arg1)) _cimg_mp_const_scalar(1/mem[arg1]);\n              _cimg_mp_scalar2(mp_div,1,arg1);\n            }\n\n            if (*ss1=='s') { // Family of 'is_?()' functions\n","sourceCodeStart":22211,"sourceCodeEnd":22247,"githubUrl":"https://github.com/Yalantis/uCrop/blob/f788b534b48c144edf786c8cddbf0e029e637804/ucrop/src/main/jni/CImg.h#L22211-L22247","documentation":"Matrix/vector reshaping functions in the parser (e.g. building a square matrix from a flat vector) accept either an implicit square shape (when nb_colsA is 0/omitted) or an explicit column count. When an explicit nb_colsA is given, the flat first argument's size p1 must equal p3*p2; if p1 is not divisible by nb_colsA, CImg throws this error naming the first argument's type (s_type(arg1)) and the column count.","triggerScenarios":"Calling a matrix-construction expression function with an explicit second argument nb_colsA that doesn't divide the length of the first vector argument, e.g. a 10-value vector with nb_colsA=3; also passing a scalar where a vector shape is required.","commonSituations":"Computing matrix dimensions by hand and miscounting elements; loading matrices saved with a different row-major/column-major layout; off-by-one truncation when serializing the matrix data.","solutions":["Make the first argument's size an exact multiple of nb_colsA (fix the data or the column count)","Omit/zero the second argument to let CImg infer a square matrix when the data is square","Verify the flattening order (row-major vs column-major) matches what the function expects","Compute nb_colsA programmatically from data.size() instead of hard-coding it"],"exampleFix":"// before\nimg.fill(\"mat([1,2,3,4,5,6,7,8,9,10],3)\"); // 10 not divisible by 3\n// after\nimg.fill(\"mat([1,2,3,4,5,6,7,8,9],3)\"); // 9 divisible by 3","handlingStrategy":"validation","validationCode":"void checkMatrixShape(double[] flat, int nbCols) {\n  if (nbCols > 0 && flat.length % nbCols != 0)\n    throw new IllegalArgumentException(\"Flat matrix size \" + flat.length + \" incompatible with nb_colsA=\" + nbCols);\n}","typeGuard":null,"tryCatchPattern":"try { img.fill(expr); } catch (CImgArgumentException e) { if (e.getMessage().contains(\"does not match with second argument 'nb_colsA'\")) { /* recompute columns or fix data length */ } throw e; }","preventionTips":["Derive nb_colsA from the data length instead of hard-coding","Pass 0/omit the second argument to get implicit square shape","Confirm flattening order when serializing matrices"],"tags":["cimg","math-parser","matrix","shape-mismatch"],"backgroundTag":"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"}