diff --git a/matrix/Matrix.hpp b/matrix/Matrix.hpp
index 188b5be619..4af752bb3e 100644
--- a/matrix/Matrix.hpp
+++ b/matrix/Matrix.hpp
@@ -352,8 +352,8 @@ public:
 
     void print(FILE *stream = stdout) const
     {
-        // element: tab, point, 8 digits; row: newline; string: \0 end
-        static const size_t n = 10*N*M + M + 1;
+        // element: tab, point, 8 digits, 4 scientific notation chars; row: newline; string: \0 end
+        static const size_t n = 15*N*M + M + 1;
         char * buf = new char[n];
         write_string(buf, n);
         fprintf(stream, "%s\n", buf);
diff --git a/test/matrixAssignment.cpp b/test/matrixAssignment.cpp
index b64a0e1b42..42523f4ca2 100644
--- a/test/matrixAssignment.cpp
+++ b/test/matrixAssignment.cpp
@@ -212,16 +212,22 @@ int main()
 
     // check write_string()
     float comma[6] = {
-        1.f, 12345.678f,
-        12345.67891f, 12345.67891f,
-        1112345.67891f, 12345.111111111f
+        1.f, 12345.123f,
+        12345.1228f, .1234567891011f,
+        12345678910.123456789f, 1234567891011.123456789101112f
     };
     Matrix<float, 3, 2> Comma(comma);
-    const size_t len = 10*2*3 + 2 + 1;
+    const size_t len = 15*2*3 + 2 + 1;
     char buffer[len];
+    Comma.print(); // for debugging in case of failure
     Comma.write_string(buffer, len);
-    char output[] = "\t       1\t12345.678\n\t12345.679\t12345.679\n\t1112345.6\t12345.111\n";
+    printf("%s\n", buffer); // for debugging in case of failure
+    char output[] = "\t       1\t12345.123\n\t12345.123\t0.12345679\n\t1.2345679e+10\t1.234568e+12\n";
+    printf("%s\n", output); // for debugging in case of failure
     for (size_t i = 0; i < len; i++) {
+        if(buffer[i] != output[i]) { // for debugging in case of failure
+            printf("%d: \"%c\" != \"%c\"", int(i), buffer[i], output[i]);
+        }
         TEST(buffer[i] == output[i]);
         if (buffer[i] == '\0') {
             break;