c++ - Android OpenCV Fatal Signal 11,(bad coding practices?) -

there isn't documentation on dreaded fatal signal 11 of opencv. can familiar opencv provide thorough explanation of causes it? seems due 'android opencv binding' in cases, in mine, not sure that's true.

though repetitive calls log, i've narrowed down exact point hit fatal signal 11.it comes before gigantic loop, shown below. i'm assuming it's memory issue since program runs function 5-30 seconds before crashing error. i'm self-taught coder, if works stick it, makes difficult me know when code being efficient or inefficient. in particular case seems causing error in c++ code don't know how debug.

    int cols = myimage.cols; int rows = myimage.rows;     (int y = 0; y < cols; y++){     (int x = 0; x < rows; x++){         //val1 = g4.at<float>(y, x);         //val2 = g5.at<float>(y, x);         if (g4.at<float>(y, x) >= minrad && g5.at<float>(y, x) >= minrad){             if (g4.at<float>(y, x) <= maxrad && g5.at<float>(y, x) <= maxrad){                 if (((x + g4.at<float>(y, x)) <= rows) && (y + g5.at<float>(y, x) <= cols)){                     mapped.at<float>(y + g5.at<float>(y, x) , y + g4.at<float>(y, x)) =              mapped.at<float>(y + g5.at<float>(y, x), y + g4.at<float>(y, x)) + 1;                     }             }         }     } } 

the full error message (shown in eclipse -- there way me garner more information on error? tried adb logcat few days ago i'm not sure whether information gave me anymore useful):

fatal signal 11 (sigsegv) @ 0x62bacfb4 (code=1), thread 24457 (thread-475) 

if leave comment explaining error message means, me too.

signal 11 segfault. means accessed memory wasn't allocated program os. given address occurred at, looks either went past bounds of array or accessed pointer never initialized. figuring out more impossible without crash trace.