Stepwise regrcls and Evri faq: Difference between pages

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imported>Donal
(Created page with "===Purpose=== STEPWISE_REGRCLS Step-wise regression for CLS models. ===Synopsis=== :[c,ikeep,res] = stepwise_regrcls(x,targspec,options); :options = stepwise_regrcls('options'...")
 
imported>Lyle
 
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===Purpose===
__TOC___
STEPWISE_REGRCLS Step-wise regression for CLS models.
==Importing / Exporting==


===Synopsis===
[[faq_concatenate_multiple_files|How do I concatenate multiple files into a single DataSet?]]
:[c,ikeep,res] = stepwise_regrcls(x,targspec,options);
:options  = stepwise_regrcls('options');


===Description===
[[faq_create_multivariate_image_from_separate_images|How do I create a multivariate image from separate images?]]
For a given set of measured spectra (x), STEPWISE_REGRCLS finds the subset of target spectra (targspec) that best fit each measured spectrum in (x). This can be used for classification i.e. an analyte identification algorithm. The model is:
    x(i,:) = c(i,:)*targspec(ikeep{i},:)
where c(i,:) can be determined using non-negative least-squares
[see optional input (options)].


===Inputs===
[[faq_export_PCA_scores_and_loadings_to_text_file|How do I export PCA scores and loadings to a text file (to read into MS Excel, for example)?]]
* '''x''' = MxN matrix of measured spectra (each row corresponds to a measured spectrum).
* '''targspec ''' = KxN matrix of target (candidate) spectra.


===Outputs===
[[faq_import_three-way_data|How do I import three-way data into Solo or PLS_Toolbox?]]
* '''c''' = MxK matrix of concentrations / contributions, c is non-zero only if a corresponding target spectrum is retained. If (options.p) is not empty, then (c) is Mx(Kp+K) where the first Kp rows correspond to the spectra in (options.p).
* '''ikeep ''' = Mx1 cell array of indices, each cell corresponds to a row of input (x) and includes the indices of retained target spectra.
* '''res ''' = Mx1 vector of mean sum-squared-residuals.


===Options===
[[faq_import_horiba_NGC_64bit |Why can't I import a Horiba NGC file on my 64-bit computer?]]
''options'' =  an optional options structure containing one or more of the following fields:


* '''display''': [ 'off' | {'on'} ], governs level of display to command window,
[[faq_SPCREADR_cant_read_multiple_files |Why can't SPCREADR read multiple files I've selected?]]
* '''automate''': [ {'yes'} | 'no' ], automate the algorithm?
:automate = 'yes', makes no plots, and the step-wise regression stops when the fit improvement is not sigificant in an F Test at the probability level given in options.fstat.
:automate = 'no', requires interactive user input for each of the M spectra in (x).


[[faq_some_EXCEL_files_fail_to_import |Why do some Excel files fail to import?]]


        fstat: 0.95, probability level the F test that determines the
==General==
                significance of fit improvement.
 
          ccon: [ 'none' | {'nnls'} ], uses non-negativity on concentrations,
[[faq_PARALIND_in_PLS_Toolbox |Can I do PARALIND in PLS_Toolbox?]]
                in the concentration estimates.
 
          ccov: [], sqrt inverse noise/clutter covariance matrix,
[[faq_install_on_more_than_one_PC | Can I install PLS_Toolbox (or Solo) on more than one PC, such as on my desktop and laptop computer?]]
                e.g. if Xc is a matrix of measured clutter spectra then
 
                ccov = inv(sqrt(cov(Xc))) [see COV_CV].
[[faq_multiple_class_sets_together_in_SIMCA_PLSDA_LDA | Can I use multiple class sets (categorical variables) together in a SIMCA, PLSDA, or LDA model?]]
            p: KpxN matrix of spectra that are always included in the
 
                model.
[[faq_more_info_on_R_Squared_statistic | Can you give me more information on the R-Squared statistic?]]
          scls: [1:N],  % 1xN spectra scale axis {default = 1:N}.
 
[[faq_how_RMSEC_and_RMSECV_related to R2Y_and_Q2Y_seen_other_software | How are RMSEC and RMSECV related to R2Y and Q2Y I see in other software?]]
 
[[faq_convergence_of_PARAFAC| Convergence of PARAFAC. How much variation between models is expected a particular PARAFAC is fit multiple times with the same settings?]]
 
[[faq_does_software_stop_working_if_maintenance_expires | Does the software stop working if my maintenance expires?]]
 
[[faq_report_a_problem_with_PLS_Toolbox | How and where do I report a problem with PLS_Toolbox?]]
 
[[faq_how_are_T_contributions_calculated | How are T-contributions calculated?]]
 
[[faq_how_are_ROC_curves_calculated_for_PLSDA | How are the ROC curves calculated for PLSDA?]]
 
[[faq_how_are_error_bars_calculated_regression_model | How are the error bars calculated for a regression model and can they be related to a confidence limit (confidence in the prediction)?]]
 
[[faq_improve_performance_with_PLS_Toolbx_and_Matlab_on_Mac | How can I improve performance with PLS_Toolbox and Matlab on the Mac platform?]]
 
[[faq_assign_classes_for_samples_in_a_DataSet | How do I assign classes for samples in a DataSet?]]
 
[[faq_build_a_classification_model_from_class_set_other_than_the_first | How do I build a classification model from a class set other than the first?]]
 
[[faq_choose_between_different_cross_validation_leave_out_options | How do I choose between the different cross-validation leave-out options?]]
 
[[faq_reference_Eigenvector| How do I cite/reference Eigenvector?]]
 
[[faq_interpret_ROC_curves_and_Sensitivity_Specificity_plots_from_PLSDA | How do I interpret the ROC curves and Sensitivity / Specificity plots from PLSDA?]]
 
[[faq_make_DataSet_backwards_compatible | How do I make a DataSet backwards compatible?]]
 
[[faq_obtain_or_use_recompilation_license_for_PLS_Toolbox | How do I obtain or use a recompilation license for PLS_Toolbox?]]
 
[[faq_use_custon_cross_validation_option | How do I use the "custom" cross-validation option?]]
 
[[faq_out_of_memory_error_when_analyzing_data | I keep getting "out of memory" errors when analyzing my data. What can I do?]]
 
[[faq_java_lang_OutOfMemoryError| What can I do if I get a java.lang.OutOfMemoryError error?]]
 
[[faq_why_get_negative_scores_when_all_modes_are_set_to_nonnegativity | Nonnegativity (PARAFAC, PARAFAC2, Tucker): Why do I get negative scores when all modes are set to nonnegativity?]]
 
[[faq_what_are_relative_contributions | What are "Relative Contributions"?]]
 
[[faq_what_are_reduced_T^2_and_Q_Statistics | What are the "Reduced" T^2 and Q Statistics?]]
 
==Command Line==
==Manual==
==GUI==
==Installation==
 
 
 
 
 
 
 
[[Category:FAQ]]

Revision as of 14:25, 29 November 2018

_

Importing / Exporting

How do I concatenate multiple files into a single DataSet?

How do I create a multivariate image from separate images?

How do I export PCA scores and loadings to a text file (to read into MS Excel, for example)?

How do I import three-way data into Solo or PLS_Toolbox?

Why can't I import a Horiba NGC file on my 64-bit computer?

Why can't SPCREADR read multiple files I've selected?

Why do some Excel files fail to import?

General

Can I do PARALIND in PLS_Toolbox?

Can I install PLS_Toolbox (or Solo) on more than one PC, such as on my desktop and laptop computer?

Can I use multiple class sets (categorical variables) together in a SIMCA, PLSDA, or LDA model?

Can you give me more information on the R-Squared statistic?

How are RMSEC and RMSECV related to R2Y and Q2Y I see in other software?

Convergence of PARAFAC. How much variation between models is expected a particular PARAFAC is fit multiple times with the same settings?

Does the software stop working if my maintenance expires?

How and where do I report a problem with PLS_Toolbox?

How are T-contributions calculated?

How are the ROC curves calculated for PLSDA?

How are the error bars calculated for a regression model and can they be related to a confidence limit (confidence in the prediction)?

How can I improve performance with PLS_Toolbox and Matlab on the Mac platform?

How do I assign classes for samples in a DataSet?

How do I build a classification model from a class set other than the first?

How do I choose between the different cross-validation leave-out options?

How do I cite/reference Eigenvector?

How do I interpret the ROC curves and Sensitivity / Specificity plots from PLSDA?

How do I make a DataSet backwards compatible?

How do I obtain or use a recompilation license for PLS_Toolbox?

How do I use the "custom" cross-validation option?

I keep getting "out of memory" errors when analyzing my data. What can I do?

What can I do if I get a java.lang.OutOfMemoryError error?

Nonnegativity (PARAFAC, PARAFAC2, Tucker): Why do I get negative scores when all modes are set to nonnegativity?

What are "Relative Contributions"?

What are the "Reduced" T^2 and Q Statistics?

Command Line

Manual

GUI

Installation

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