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Program MAP_NEURAL_CREEP

  1. Provenance of code.
  2. Purpose of code.
  3. Specification.
  4. Description of subroutine's operation.
  5. PC Files
  6. UNIX Files
  7. References.
  8. Parameter descriptions.
  9. Error indicators.
  10. Accuracy estimate.
  11. Any additional information.
  12. Example of code
  13. Auxiliary subroutines required.
  14. Keywords.
  15. Download source code.
  16. Links.

Provenance of Source Code

David Cole and H.K.D.H. Bhadeshia,
Phase Transformations Group,
Department of Materials Science and Metallurgy,
University of Cambridge,
Cambridge, U.K.

The neural network program was produced by:

David MacKay,
Cavendish Laboratory,
University of Cambridge,
Madingley Road,
Cambridge, CB3 0HE, U.K.

Added to MAP: Nov 1999

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Purpose

To estimate the creep rupture strength of ferritic power plant steels at a certain temperature, as a function of chemical composition, heat treatments and time.

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Specification

Language:FORTRAN / C
Product form:Source code / Executable files
Operating System:Solaris 5.5.1 & Windows 95

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Description

MAP_NEURAL_CREEP contains a suite of programs which enable the user to estimate the creep rupture strength of ferritic power plant steels as a function of composition, heta treatment, temperature and time. It makes use of a neural network program called generate44, which was developed by David MacKay and is part of the bigback5 program. The network was trained using a large database of experimental results [1] (some of these data are available on MAP under the Materials Data section as MAP_DATA_CREEP_RUPTURE. Eleven models are used for the creep rupture strength calculations which differ from each other by the number of hidden units and by the value of the seed used when training the network. It was found that a more accurate result could be obtained by averaging the results from all the models [1]. This suite of programs calculates the results of each model and then combines them, by averaging, to produce a committee result and error estimate, as described by MacKay [page 387 of reference 2]. The source code for the neural network program can be downloaded from David MacKay's website; the executable files only are available from MAP. Also provided are FORTRAN programs (as source code) for normalising the input data, averaging the results from the neural network program and unnormalising the final output file, along with other files necessary for running the program.

Programs are available which run on a Solaris 5.5.1 unix system and on a PC under Windows 95. A distinct set of program and data files are provided and each directory or zip file contains the following files and subdirectories:

PC Files

README
A text file containing step-by-step instructions for running the program, including a list of input variables.

Minmax
A text file containing the minimum and maximum limits of each input and output variable. This file is used to normalise and unnormalise the input and output data.

test.dat
An input text file containing the input variables used for predictions.

no_of_rows.dat
This text file contains the number of rows of data in the file test.dat

creep.exe
This executable program for the PC corresponds to the unix command file predict. The source code is given in creep.c which is in subdirectory s.

spec_D.ex
This executable file reads the information in no_of_rows.dat and creates a file called spec.t1.

spec.t1
A dynamic file, created by spec_D.exe, which contains information about the module and the number of data items being supplied. It is read by the program generate55.

norm_test.in
This a text file which contains the normalised input variables. It is generated by the program normtest.for in subdirectory s.

generate55
This is the executable file for the neural network program and runs on the PC. It reads the normalised input data file, norm_test.in, and uses the weight files in subdirectory c, to find a value for either the creep rupture strength. The results are written to the temporary output file _out.

_ot, _out, _res, _sen
These files are created by generate55 and can be deleted.

Result.dat
Contains the final un-normalised committee results for the predicted creep rupture strength.


SUBDIRECTORY s

spec_D.c
The source code for program spec_D.ex.

normtest.for
Program to normalise the data in test.dat and produce the normalised input file norm_test.in. It makes use of information read in from no_of_rows.dat and committee.dat.

gencom.for
This program uses the information in committee.dat and combines the predictions from the individual models, in subdirectory outprdt, to obtain an averaged value (committee prediction). The output (in normalised form) is written to com.dat.

treatout.for
Program to un-normalise the committee results in com.dat and write the output predictions to unnorm_com. This file is then renamed Result.dat.

committee.dat
A text file containing the number of models to be used to form the committee result and the number of input variables. It is read by gencom.for, normtest.for and treatout.for.


SUBDIRECTORY c

_w*f
The weights files for the different models.

*.lu
Files containing information for calculating the size of the error bars for the different models.

_c*
Files containing information about the perceived significance value for each model.

_R*
Files containing values for the noise, test error and log predictive error for each model.


SUBDIRECTORY d

outran.x
A normalised output file which was created during the building of the model. It is accessed by generate55 via spec.t1.


SUBDIRECTORY outprdt

out1, out2 etc.
The normalised output files for each model.

com.dat
The normalised output file containing the committee results. It is generated by gencom.for.

UNIX Files

These are as the PC Files except for the following:


pred.dat
As test.dat, but the first row of this file has to be the number of input lines in the file.

length
As no_of_rows.dat.

run.genpred
This file contains the commands necessary for running generate44 (as generate55, but the UNIX version) and producing the final committee result.

predict
A unix shell file containing the commands to run the entire module. It can be executed by typing predict at the command prompt. This file runs all the programs necessary for normalising the input data, executing the network for each model, unnormalising the output data and combining the results of each model to produce the final committee result. This corresponds to the PC file creep.exe

spec.pred
A file which contains information about the module and is read by generate44. This has to be changed to allow for input files of varying size. The data corresponding to 'Number_data' and 'Train_from_1_to_this' has to be changed to the number of rows in the input file, not including the first row, which will be the length of the file. 'Test_set_1' and 'Test_set_2' have to have the frist column set to 1 and then the second column set to the number of input rows.

generate44
The UNIX version of generate55.

outnorm.out
As Result.dat.

PRN
Contains the normalised input file.

normtargetnn
Contains the normalised target file.

SUBDIRECTORY s

Contains the fortran files for the UNIX module versions of normtest.for, gencom.for and treatout.for which are norm.for, gencom.for and unnormout.for respectively.


IMPORTANT

Detailed instructions on the use of the program are given in the README files. Further information about this suite of programs can be obtained from reference 1.


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References

  1. D. G. Cole, C. Martin-Moran, A. G. Sheard, H. K. D. H. Bhadeshia and D. J. C. MacKay, 1999, Science and Technology of Welding and Joining, Accepted for publication.
  2. D.J.C. MacKay, 1997, Mathematical Modelling of Weld Phenomena 3, eds. H Cerjak & H.K.D.H. Bhadeshia, Inst. of Materials, pp 359.
  3. D.J.C MacKay's website at http://wol.inference.phy.cam.ac.uk/mackay/README.html#Source_code

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Parameters

Input parameters

The input variables for each module are listed in the README file in the corresponding directory. The maximum and minimum values for each variable are given in the file MINMAX.

Output parameters

These programs give either the yield strength or the ultimate tensile strength value in MPa. The corresponding output file is called Result.dat. The format of the output file is:

Prediction   	Prediction -  Error	Prediction + Error
  (MPa)              (MPa)                   (MPa)

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Error Indicators

None.

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Accuracy

A full calculation of the error bars is presented in reference 1.

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Further Comments

None.

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Example

1. Program text

       Complete program.

2. Program data

See sample data file: test.dat / pred.dat.

3. Program results

See sample output file: Result.dat or outnorm.out.

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Auxiliary Routines

None

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Keywords

neural network, creep rupture strength

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Download

Download MAP information files

Solaris.5.5.1:
Download UNIX module (gzip tar file, 52 Mbytes)

Linux Software:
Download Linux module (gzip tar file, 52 Mbytes)

PC Software:
Download Module (30 Mbytes)

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MAP originated from a joint project of the National Physical Laboratory and the University of Cambridge.

MAP Website administration / map@msm.cam.ac.uk

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