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Deklaration von symbolischer Variable funktioniert nicht |
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Forum-Newbie
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Beiträge: 2
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Anmeldedatum: 10.06.18
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Wohnort: ---
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Version: ---
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Verfasst am: 10.06.2018, 11:57
Titel: Deklaration von symbolischer Variable funktioniert nicht
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Hallo, ich habe einen Code mit symbolischen Variablen geschrieben. Dieser wurde zum Teil mit Matlab 2017 und zum Teil mit 2018 verfasst. Bis gestern lief der Code einwandfrei. Nun kommt mein Code bei der Deklaration von symbolischen Variablen nicht mehr weiter. Der RAM (16 Gb) wird nach einigen Minuten voll.
Selbst die Beispiele aus Matlab kann mein PC nun nicht mehr lösen. Nach dem Debuggen hängt der Code an der Deklarationszeile. Das Problem existiert an zwei PCs mit Matlab 2018.
Die Symbolic Math Toolbox besitze ich.
Einfaches Beispiel, welches nicht läuft:
clc
clear
clear all
syms x
f(x) = 5*x+1;
res = f(1)
Ich bin im Moment wirklich ratlos und bedanke mich vorab für eure Hilfe.
Der Debugger zeigt nach dem Pausieren folgendes an:
Der Pausiervorgang dauert übrigens auch weit über eine Minute.
function y = sympref(varargin)
%SYMPREF Set and get symbolic preferences.
% SYMPREF determines the preferences for some symbolic functions.
% When these preferences are changed, the new values are used
% immediately. They persist in future MATLAB sessions until they
% are changed again.
%
% CURRENT = SYMPREF returns a structure array with currently
% used preferences. The values of the preferences are returned
% as SYM objects.
%
% CURRENT = SYMPREF(NAME) returns the current value of the
% preference given by the string NAME as a SYM object OLD.
% NAME takes the string inputs 'FourierParameters' or
% 'HeavisideAtOrigin'.
%
% OLD = SYMPREF(NAME, NEW) sets the preference given by the
% string NAME to the value NEW. The old value is returned in
% the SYM object OLD.
% For 'FourierParameters', the value NEW must be a numeric or
% symbolic vector of length two. Its entries determine the
% definition of the Fourier transform and its inverse used by
% the functions FOURIER and IFOURIER. The default value is [1,-1].
% For 'HeavisideAtOrigin', the value NEW must be a numeric scalar
% or a scalar SYM object. It determines the result of the function
% HEAVISIDE at the origin. Useful values are 0, 1/2, or 1. The
% default value is 1/2.
% For 'AbbreviateOutput', the value NEW must be convertible into a
% logical scalar. If TRUE, the output of PRETTY and typesetting
% output in Live Script use abbreviations.
% For 'TypesetOutput', the value NEW must be convertible into a
% logical scalar. If TRUE, the output of SYMs in Live Script will
% use typesetting.
%
% OLD = SYMPREF(NAME, 'default') sets the preference given
% by the string NAME to its default value. The old value is
% returned in the SYM object OLD.
%
% OLD = SYMPREF('default') sets all preferences to their
% default values and returns a structure array with the old
% preferences given by SYM values.
%
% OLD = SYMPREF(NEW) sets all preferences to values given by the
% structure array NEW. Valid input structure arrays are given
% by output values of SYMPREF or SYMPREF('default'). The old
% values of preferences are returned in the structure array
% array OLD that is also valid input for a call to SYMPREF.
%
% You should change symbolic preferences only at the beginning
% of a MATLAB session.
%
% Example:
% >> heaviside(0)
% ans =
%
% 0.5000
% Change heaviside(0) by setting a new preference:
% >> old = sympref('HeavisideAtOrigin', 1);
% >> heaviside(0)
% ans =
%
% 1
% Restore the original preference:
% >> sympref('HeavisideAtOrigin', old);
%
% See also DISP, DISPLAY, FOURIER, IFOURIER, HEAVISIDE, PRETTY.
% Copyright 2014-2016 The MathWorks, Inc.
narginchk(0,2);
s = settings;
if ~s.hasGroup('symbolic_internal')
initializeSymprefs;
end
if nargin == 0
y = getAllPrefs;
return;
end
varargin = sym.convertStrings(varargin);
prefname = varargin{1};
iSymprefs = implementedSymprefs;
if nargin == 1 && isstruct(prefname)
y = getAllPrefs;
prefnames = fieldnames(prefname);
prefvalues = struct2cell(prefname);
prefnames = cellfun(@validateprefname,prefnames,'UniformOutput',false);
% replace the strings 'default' by the default values
pprefvalues = cellfun(@validateprefvalue,prefvalues,'UniformOutput',false);
pos = strcmpi(pprefvalues( , 'default');
defaults = implementedSymprefs;
prefvalues(pos) = defaults(pos,2);
setSMTpref(prefnames, prefvalues);
setMuPADpref(prefnames, prefvalues);
return;
end
if ~ischar(prefname)
error(message('symbolic:sympref:ExpectingString'));
end
if nargin == 1
if strcmpi(prefname,'Initialize')
initializeSymprefs;
y = [];
else
prefname = validatestring(prefname,{iSymprefs{:,1},'default'});
if strcmpi(prefname,'default')
y = setSMTpref(iSymprefs(:,1), iSymprefs(:,2));
setMuPADpref(iSymprefs(:,1), iSymprefs(:,2));
y = cell2struct(y,iSymprefs(:,1),1);
else
currentPrefs = getAllPrefs;
y = currentPrefs.(prefname);
end
end
else % nargin == 2
prefname = validatestring(prefname,iSymprefs(:,1));
prefvalue = varargin{2};
expectedType = expectedPrefType(prefname);
if ischar(prefvalue)
validatestring(prefvalue,{'default'});
prefvalue = getDefault(prefname);
end
y = setSMTpref(prefname, prefvalue);
try
prefvalue = convert2expectedtype(prefvalue,expectedType);
% check if prefvalue is accepted by MuPAD
setMuPADpref(prefname, prefvalue);
catch
% restore the original prefvalue
setSMTpref(prefname, y);
error(message('symbolic:sympref:CannotSetPref', prefname));
end
end
end
% =====================================
% Add further settings/preferences here.
% Also add them to symprefValidator!
% =====================================
function y = implementedSymprefs
y = {'FourierParameters', sym([1,-1]), 'MuPAD', 'sym';...
'HeavisideAtOrigin', sym(1/2), 'MuPAD', 'sym';...
'AbbreviateOutput', true, 'MuPAD', 'logical';...
'TypesetOutput', true, 'SMT', 'logical';...
};
end
function y = symprefValidator(prefname,prefvalue,expectedType)
% do not allow string input
switch expectedType
case 'sym'
if isnumeric(prefvalue)
prefvalue = sym(prefvalue);
end
if isa(prefvalue, 'symfun')
prefvalue = formula(prefvalue);
end
try
prefvalue = sym(prefvalue);
catch
error(message('symbolic:sympref:ValueMustBeNumericOrSym', prefname));
end
case 'logical'
try
prefvalue = logical(prefvalue);
catch
error(message('symbolic:sympref:ValueMustBeLogical', prefname));
end
if ~isscalar(prefvalue)
error(message('symbolic:sympref:ValueMustBeLogical', prefname));
end
end
switch prefname
case 'FourierParameters'
if ~(isvector(prefvalue) && length(prefvalue)==2)
error(message('symbolic:sympref:CannotSetPref', prefname));
end
if ~all(isfinite(prefvalue))
error(message('symbolic:sympref:MustBeFinite', prefname));
end
case 'HeavisideAtOrigin'
if ~isscalar(prefvalue)
error(message('symbolic:sympref:CannotSetPref', prefname));
end
if ~isfinite(prefvalue)
error(message('symbolic:sympref:MustBeFinite', prefname));
end
end
y = prefvalue;
end
% =========================
% various further utilities
% =========================
function y = convert2basetype(x)
if islogical(x)
y=x;
return;
end
y = ['symobj::fromString("' char(feval(symengine,'symobj::toString',x)) '",2)'];
end
function y = convert2expectedtype(x,expectedType)
if strcmp(expectedType, 'sym') && ischar(x)
y = evalin(symengine, x);
else
y = feval(expectedType, x);
end
end
function initializeSymprefs
s = settings;
if ~s.hasGroup('symbolic_internal')
s.addGroup('symbolic_internal','hidden',true);
end
group = s.symbolic_internal;
iSymprefs = implementedSymprefs;
for i=1:size(iSymprefs,1)
prefname = iSymprefs{i,1};
expectedType = iSymprefs{i,4};
if ~group.hasSetting(prefname)
group.addSetting(prefname,'hidden',true);
end
prefnamesetting = group.(prefname);
if ~(prefnamesetting.hasTemporaryValue || prefnamesetting.hasPersonalValue || prefnamesetting.hasFactoryValue)
prefnamesetting.PersonalValue = convert2basetype(iSymprefs{i,2});
end
try
prefvalue = convert2expectedtype(prefnamesetting.ActiveValue,expectedType);
setMuPADpref(prefname, prefvalue);
catch
% if the prefvalue in the XML file is not accepted
% by MuPAD, fall back to the default value
prefvalue = convert2expectedtype(iSymprefs{i,2},expectedType);
setMuPADpref(prefname, prefvalue);
prefnamesetting.PersonalValue = convert2basetype(iSymprefs{i,2});
warning(message('symbolic:sympref:CannotSetPref',prefname));
end
end
return;
end
function y = validateprefname(prefname)
iSymprefs = implementedSymprefs;
y = validatestring(prefname, iSymprefs(:,1));
end
function y = validateprefvalue(prefvalue)
if ischar(prefvalue)
y = validatestring(prefvalue, {'default'});
else
y = prefvalue;
end
end
function y = getAllPrefs
s = settings;
group = s.symbolic_internal;
iSymprefs = implementedSymprefs;
for i=1:size(iSymprefs,1)
prefname = iSymprefs{i,1};
expectedType = iSymprefs{i,4};
if group.hasSetting(prefname)
settingsprefname = group.(prefname);
if(settingsprefname.hasTemporaryValue || settingsprefname.hasPersonalValue || settingsprefname.hasFactoryValue)
iSymprefs{i,2} = convert2expectedtype(settingsprefname.ActiveValue,expectedType);
end
end
end
y = cell2struct(iSymprefs(:,2),iSymprefs(:,1),1);
end
function y = setSMTpref(prefname, prefvalue)
s = settings;
group = s.symbolic_internal;
if ischar(prefname)
if ~group.hasSetting(prefname)
group.addSetting(prefname,'hidden',true);
end
expectedType = expectedPrefType(prefname);
settingsprefname = group.(prefname);
if ~(settingsprefname.hasTemporaryValue || settingsprefname.hasPersonalValue || settingsprefname.hasFactoryValue)
y = getDefault(prefname);
else
try
y = convert2expectedtype(settingsprefname.ActiveValue,expectedType);
catch
% The storarge was messed up.
y = getDefault(prefname);
end
end
prefvalue=symprefValidator(prefname,prefvalue,expectedType);
settingsprefname.PersonalValue = convert2basetype(prefvalue);
if strcmpi(prefname, 'HeavisideAtOrigin')
heaviside('Clear');
end
else
assert(iscell(prefname) && iscell(prefvalue));
y = cellfun(@setSMTpref,prefname,prefvalue,'UniformOutput',false);
end
end
function setMuPADpref(prefname, prefvalue)
if ischar(prefname)
if isMuPADPref(prefname)
if strcmpi(expectedPrefType(prefname), 'logical')
if prefvalue
prefvalue = 'TRUE';
else
prefvalue = 'FALSE';
end
end
MuPADprefname = ['Pref::' lower(prefname(1)) prefname(2:end)];
feval(symengine,MuPADprefname,prefvalue);
end
else
assert(iscell(prefname) && iscell(prefvalue));
cellfun(@setMuPADpref, prefname, prefvalue, 'UniformOutput',false);
end
end
function y = getDefault(prefname)
iSymprefs = implementedSymprefs;
pos = strcmpi(iSymprefs(:,1),prefname);
y = iSymprefs{pos,2};
end
function y = isMuPADPref(prefname)
iSymprefs = implementedSymprefs;
pos = strcmpi(iSymprefs(:,1),prefname);
y = strcmpi(iSymprefs{pos,3},'MuPAD');
end
function y = expectedPrefType(prefname)
iSymprefs = implementedSymprefs;
pos = strcmpi(iSymprefs(:,1),prefname);
y = iSymprefs{pos,4};
end
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Themenstarter
Forum-Newbie
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Beiträge: 2
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Anmeldedatum: 10.06.18
|
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|
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Wohnort: ---
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Version: ---
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Verfasst am: 10.06.2018, 13:28
Titel:
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