{"record":{"id":"685271d764d64cfb","repo":"Yalantis/uCrop","slug":"invert-lapack-function-dgetri-returned-error","errorCode":null,"errorMessage":"invert(): LAPACK function dgetri_() returned error code %d.","messagePattern":"invert\\(\\): LAPACK function dgetri_\\(\\) returned error code (.+?)\\.","errorType":"console","errorClass":null,"httpStatus":null,"severity":"warning","filePath":"ucrop/src/main/jni/CImg.h","lineNumber":32876,"sourceCode":"        _data[6] = (T)((b*f - e*c)/dete), _data[7] = (T)((d*c - a*f)/dete), _data[8] = (T)((a*e - d*b)/dete);\n      } else {\n\n#ifdef cimg_use_lapack\n        int INFO = (int)use_LU, N = _width, LWORK = 4*N, *const IPIV = new int[N];\n        Tfloat\n          *const lapA = new Tfloat[N*N],\n          *const WORK = new Tfloat[LWORK];\n        cimg_forXY(*this,k,l) lapA[k*N + l] = (Tfloat)((*this)(k,l));\n        cimg::getrf(N,lapA,IPIV,INFO);\n        if (INFO)\n          cimg::warn(_cimg_instance\n                     \"invert(): LAPACK function dgetrf_() returned error code %d.\",\n                     cimg_instance,\n                     INFO);\n        else {\n          cimg::getri(N,lapA,IPIV,WORK,LWORK,INFO);\n          if (INFO)\n            cimg::warn(_cimg_instance\n                       \"invert(): LAPACK function dgetri_() returned error code %d.\",\n                       cimg_instance,\n                       INFO);\n        }\n        if (!INFO) cimg_forXY(*this,k,l) (*this)(k,l) = (T)(lapA[k*N + l]); else fill(0);\n        delete[] IPIV; delete[] lapA; delete[] WORK;\n#else\n        if (use_LU) { // LU solver\n          CImg<Tfloat> A(*this,false), indx;\n          bool d;\n          A._LU(indx,d);\n          cimg_pragma_openmp(parallel for cimg_openmp_if_size(_width*_height,16*16))\n          cimg_forX(*this,j) {\n            CImg<Tfloat> col(1,_width,1,1,0);\n            col(j) = 1;\n            col._solve(A,indx);\n            cimg_forX(*this,i) (*this)(j,i) = (T)col(i);\n          }","sourceCodeStart":32858,"sourceCodeEnd":32894,"githubUrl":"https://github.com/Yalantis/uCrop/blob/f788b534b48c144edf786c8cddbf0e029e637804/ucrop/src/main/jni/CImg.h#L32858-L32894","documentation":"After a successful LU factorization, CImg::invert() calls LAPACK dgetri_() to compute the inverse; nonzero INFO means the inversion step failed (dgetri_ reports an invalid argument or an internal pivot problem). CImg then fills the matrix with zeros rather than throwing.","triggerScenarios":"Calling invert(use_LU=true) when dgetri_ receives bad parameters — typically caused by an inconsistent matrix size, a corrupted IPIV pivot array, or insufficient WORK space on unusual builds.","commonSituations":"Very large matrices exceeding LAPACK integer ranges; custom/incomplete LAPACK builds in the JNI/NDK environment with mismatched dgetri_ signatures.","solutions":["Verify the matrix is square and reasonably sized before calling invert()","Use a consistent, complete LAPACK build in the NDK project (check that dgetrf_/dgetri_ come from the same library)","Check the zero-filled result and fall back to an alternative inversion (e.g. solve-based or eigen-based)","Reduce matrix dimensions or use block-wise inversion for huge matrices"],"exampleFix":"// before\nCImg<float> inv = A.invert(true);\n// after\nif (A.width() != A.height() || A.width() == 0) throw std::runtime_error(\"invert needs a non-empty square matrix\");\nCImg<float> inv = A.invert(true);","handlingStrategy":"validation","validationCode":"bool okForInvert(const CImg<float>& A) {\n  return A.width() == A.height() && A.width() > 0 && A.width() < 100000;\n}","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Validate square, non-empty matrices before invert()","Keep LAPACK dgetrf_/dgetri_ from the same library build","Verify the result is non-zero before using it","For huge matrices, use block or iterative methods"],"tags":["cimg","lapack","linear-algebra","matrix-inverse"],"backgroundTag":"lapack-solver-failed","analyzedSha":"f788b534b48c144edf786c8cddbf0e029e637804","analyzedAt":"2026-09-08T08:36:04.887Z","contentChangedAt":"2026-09-08T08:36:04.887Z","schemaVersion":2},"datasetVersion":"2026-09-14T11:17:12.474Z"}