diff --git a/include/ceres/solver.h b/include/ceres/solver.h
index 15fd733..bd66927 100644
--- a/include/ceres/solver.h
+++ b/include/ceres/solver.h
@@ -83,7 +83,8 @@
       minimizer_progress_to_stdout = false;
       return_initial_residuals = false;
       return_final_residuals = false;
-      lsqp_dump_format = "lm_iteration_%03d.lsqp";
+      lsqp_dump_directory = "/tmp";
+      lsqp_dump_format_type = TEXTFILE;
       crash_and_dump_lsqp_on_failure = false;
       check_gradients = false;
       gradient_check_relative_precision = 1e-8;
@@ -213,12 +214,8 @@
     //
     // This is ignored if protocol buffers are disabled.
     vector<int> lsqp_iterations_to_dump;
-
-    // Format string for the file name used for dumping the least
-    // squares problem to disk. If the format is 'ascii', then the
-    // problem is logged to the screen; don't try this with large
-    // problems or expect a frozen terminal.
-    string lsqp_dump_format;
+    string lsqp_dump_directory;
+    DumpFormatType lsqp_dump_format_type;
 
     // Dump the linear least squares problem to disk if the minimizer
     // fails due to NUMERICAL_FAILURE and crash the process. This flag
diff --git a/include/ceres/types.h b/include/ceres/types.h
index b83a266..433baa8 100644
--- a/include/ceres/types.h
+++ b/include/ceres/types.h
@@ -210,6 +210,33 @@
   SOLVER_TERMINATE_SUCCESSFULLY
 };
 
+// The format in which linear least squares problems should be logged
+// when Solver::Options::lsqp_iterations_to_dump is non-empty.
+enum DumpFormatType {
+  // Print the linear least squares problem in a human readable format
+  // to stderr. The Jacobian is printed as a dense matrix. The vectors
+  // D, x and f are printed as dense vectors. This should only be used
+  // for small problems.
+  CONSOLE,
+
+  // Write out the linear least squares problem to the directory
+  // pointed to by Solver::Options::lsqp_dump_directory as a protocol
+  // buffer. linear_least_squares_problems.h/cc contains routines for
+  // loading these problems. For details on the on disk format used,
+  // see matrix.proto. The files are named lm_iteration_???.lsqp.
+  PROTOBUF,
+
+  // Write out the linear least squares problem to the directory
+  // pointed to by Solver::Options::lsqp_dump_directory as text files
+  // which can be read into MATLAB/Octave. The Jacobian is dumped as a
+  // text file containing (i,j,s) triplets, the vectors D, x and f are
+  // dumped as text files containing a list of their values.
+  //
+  // A MATLAB/octave script called lm_iteration_???.m is also output,
+  // which can be used to parse and load the problem into memory.
+  TEXTFILE
+};
+
 const char* LinearSolverTypeToString(LinearSolverType type);
 const char* PreconditionerTypeToString(PreconditionerType type);
 const char* LinearSolverTerminationTypeToString(