Wednesday, October 28, 2009

Flood - An open source Neural Networks C++ Library

Today, I found another Open source Neural Network library: Flood.

Testing ...
Maybe it would be helpful.

To install it on Linux, add one more code to the file: Flood2/Flood/Utilities/Vector.h
include <stdlib.h>

otherwise when compiling, it will give errors that function "exit" not defined.

Tuesday, October 27, 2009

Quicknet - Bug for Learning Partial Weights

In the previous post, I have do some modification to enable the Quicknet for learning arbitrary weight sections.

However, there is still a bug which I just found it.

In the original Quicknet design, the partial weights that can be learned is only the last part. By last part, suppose for a 4 layer MLP, the parameter "mlp_lrmultiplier" is set to be "x,y,z", x control the weight between layer 1 and layer 2, y controls the weight between layer 2 and layer 3, and z controls the weight between layer 3 and layer 4.

If we set y to be 0, then no matter what value z is set, the actual z used in Quicknet is 1. That means after the first un-updated weight section, the following weights are all un-updated.

Also in the original design, if the weight is no updated, the error will not be back propagated through that layer.

All in all, in the last modification we should not remove the "break" sentences.

The new version can be found here.

Monday, October 12, 2009

Quicknet - Enable Learning Partial Weights

As in the original Quicknet_v3_20, the parameter mlp_lrmultiplier can scale the learning rate per-section. If the value is set to 0.0, then that section weight will not be updated. However, only it does not provide full freedom to set any section to be kept during training. As the values after the first non-zero value will be non zeros.

To remove this restrict, following steps need to be done:
QN_MLP_BunchFlVar::train_bunch() function:
about line 427:
if (cur_layer!=nlayers-1 && backprop_weights[cur_weinum+1])

ToDo: remove "&& backprop_weights[cur_weinum+1]"

QN_MLP_BaseFl::set_learnrate() function:
about line 334:

ToDo: remove these two sentences.

The workable sourcecode, at least works for my purpose, can be found here:

Friday, October 9, 2009

Quicknet_v3_20 Bug-I

There is a small bug in the softtarget trainer.

After the pre-run cross validation, the qnmultitrn stopped and gave out the error "segmentation fault".

This bug is simply because that in the file "", in the function(begins at line 598):

// "Soft training" object - trains using continuous targets.

QN_SoftSentTrainer::QN_SoftSentTrainer(int a_debug, const char* a_dbgname,
                       int a_verbose,
                       QN_MLP* a_mlp,
                       QN_InFtrStream* a_train_ftr_str,
                       QN_InFtrStream* a_train_targ_str,
                       QN_InFtrStream* a_cv_ftr_str,
                       QN_InFtrStream* a_cv_targ_str,
                       QN_RateSchedule* a_lr_sched,
                       float a_targ_low, float a_targ_high,
                       const char* a_wlog_template,
                       QN_WeightFileType a_wfile_format,
                       const char* a_ckpt_template,
                       QN_WeightFileType a_ckpt_format,
                       unsigned long a_ckpt_secs,
                       size_t a_bunch_size,
                       float* a_lrscale)
    : clog(a_debug, "QN_SoftSentTrainer", a_dbgname),

Two variable debug and dbgname is not initialized. As debug is an integer, the uninitialized variable did not cause big problem. However, dbgname is a pointer which casued the "Segmentation fault".

To fix this bug only add the following two blue lines in the code.
    : debug(a_debug),

      clog(a_debug, "QN_SoftSentTrainer", a_dbgname),