Data processing in MathCAD
Data in tables Tables are analogous to matricesTables are analogous to matrices The numbers of columns and rows can be dynamically The numbers of columns and rows can be dynamically
changed (in contrast to matrix)changed (in contrast to matrix) To enter table:To enter table:
Menu: Insert/Data/Table (MC v. 15)Menu: Insert/Data/Table (MC v. 15) In placeholder type variable name which will be In placeholder type variable name which will be
assigned to tableassigned to table In cells type the valuesIn cells type the values Each rows and columns must contains the same Each rows and columns must contains the same
number of data. If data are missing the value ‘0’ will number of data. If data are missing the value ‘0’ will be assignedbe assigned
Access to data in table is similar to the one in matrix Access to data in table is similar to the one in matrix case. case.
Data in tables
Data in tables RowRow/column/column appears appears in table in table when only 1 data is when only 1 data is
inserted into the cell:inserted into the cell: tabletable size = specified cell in the lowest row and size = specified cell in the lowest row and
in last column in last column Unfilled cells contains 0Unfilled cells contains 0 Once specified cell can not be removedOnce specified cell can not be removed!!
To overcome problem: create new matrix To overcome problem: create new matrix with correct number of rows with correct number of rows ii and columns and columns jj usingusing
jiji ,, OLDNEW
External data sources: Data in files
The most popular file formats accepted by MathCAD:The most popular file formats accepted by MathCAD: Text filesText files Excel worksheetsExcel worksheets
To insert text file containing data: To insert text file containing data: Menu: Insert/Data/File InputMenu: Insert/Data/File Input Chose file formatChose file format Browse to the file locationBrowse to the file location
path could be relative or absolutepath could be relative or absolute In the placeholder type variable name that will be In the placeholder type variable name that will be
assigned to the contents of fileassigned to the contents of file
Inserting the text file
Inserting the text file Changes in the text file locationChanges in the text file location
Inserting the Excel worksheets A range of Excel cells can be inserted into the A range of Excel cells can be inserted into the
MathCADMathCAD There can be more then one range in single There can be more then one range in single
insertioninsertion One variable is being assigned to one rangeOne variable is being assigned to one range All variables forms a vectorAll variables forms a vector Cells can contain numbers as well as text (in Cells can contain numbers as well as text (in
contrast to table and text filescontrast to table and text files, ver. 2001, ver. 2001)) Worksheets can be edited (double-click) using Worksheets can be edited (double-click) using
all Excel functions (object embeddedall Excel functions (object embedded - -Excel Excel has to be installed in systemhas to be installed in system))..
Inserting the Excel sheets
To insert worksheet:To insert worksheet: Menu: Insert/Component/ExcelMenu: Insert/Component/Excel Browse file or create newBrowse file or create new Choose number of ranges for input and output Choose number of ranges for input and output
((relatively to Excel worksheetrelatively to Excel worksheet). If no data have to ). If no data have to be inserted into thebe inserted into the Excel Excel worksheet worksheet fillfill inputs inputs numbernumber by by 0 0
Type ranges corresponding to outputsType ranges corresponding to outputs – e.g. A1:B10 – e.g. A1:B10 ((ifif workworksheet name isheet name iss different from Sheet1 type different from Sheet1 type sheet namesheet name – e.g. Sheet4!A1:B10 – e.g. Sheet4!A1:B10))
In placeholder(s) type variable(s) In placeholder(s) type variable(s) Number of outputs/inputs and range of cells can be Number of outputs/inputs and range of cells can be
edited in properties of insertionedited in properties of insertion
MathCAD files as data source in MathCAD Main Main MathCAD MathCAD document document can use data included in can use data included in
other MathCAD other MathCAD documentsdocuments Access to data is possible after embedding MathCAD Access to data is possible after embedding MathCAD
file:file: menu: Insert/References, menu: Insert/References, Brows Brows the the filefile Below the insertion Below the insertion point point all data, definitions from all data, definitions from
inserted file are valid in the inserted file are valid in the mainmain document but document but worksheet options from main document overwrite worksheet options from main document overwrite options in inserted documentoptions in inserted document
Problem: matrix/vector elements numbers when Problem: matrix/vector elements numbers when array origin is different in main and inserted doc. array origin is different in main and inserted doc.
Data analysis and optimisation
ApproximationApproximation
definition
Approximation is a part of numerical Approximation is a part of numerical analysis. It is concerned with how functions analysis. It is concerned with how functions ff((xx) can be best approximated ) can be best approximated ((fittedfitted) ) with with another functions another functions FF((xx))
application Simplifying calculations when original Simplifying calculations when original
function function ff((xx) is defined by complicated ) is defined by complicated expression expression
designdesign of continuous dependency when of continuous dependency when function function ff((xx) is ) is describeddescribed on discrete set of on discrete set of arguments. arguments. If the form of approximating If the form of approximating function is given only values of function function is given only values of function parameters showing the best approximation parameters showing the best approximation have to behave to be determine. determine.
types of approximation
Interpolating approximationInterpolating approximation
Uniform approximationUniform approximation
Square-mean approximation Square-mean approximation
Interpolating approximation NeedNeedss to satisfy condition: function given to satisfy condition: function given
ff((xx) and approximating function ) and approximating function FF((xx) have ) have the same values on the set of nodes and the same values on the set of nodes and (sometimes) the same values of derivatives (sometimes) the same values of derivatives ((if givenif given)) too. too.
1 1.5 2 2.5 3 3.5 410
20
30
40
50
60
7069
12
f a( )
z
41 a x
Uniform approximation
Function Function FF((xx) approximating function ) approximating function ff((xx) ) in the range [in the range [aa,,bb], satisfying condition], satisfying condition:: maximal residuum maximal residuum is set tois set to minimum minimum
Square-mean approximation
Approximating function is determined by Approximating function is determined by the use of condition:the use of condition:
Geometrically condition means: The area Geometrically condition means: The area between curves representing functions have between curves representing functions have to reach minimum. to reach minimum.
min2 dxxfxFEb
a
Condition for discreet set of arguments:Condition for discreet set of arguments:
min2
iii xfxFE
Square-mean approximation
Function:Function:
minimize(minimize(functionfunction, , pp1, 1, pp2,...)2,...)
can be used to determine parameters of can be used to determine parameters of approximating function minimizing the sum of approximating function minimizing the sum of square deviations between values given in the square deviations between values given in the table and calculated from the function.table and calculated from the function. functionfunction calculates the sum of square calculates the sum of square
deviations as a function of parameters.deviations as a function of parameters. pp1, 1, pp2 – parameters of approximating function2 – parameters of approximating function
Square-mean approximation in MathCAD
Approximating algorithm:Approximating algorithm:1.1. Insert data to be approximatedInsert data to be approximated2.2. Build the approximating functionBuild the approximating function3.3. Create a counting variable with values from 0 Create a counting variable with values from 0
to number of data minus 1to number of data minus 14.4. Build function Build function EE that calculates sum of square that calculates sum of square
of deviations with parameters of of deviations with parameters of approximating function as variablesapproximating function as variables
5.5. Assign starting values of parametersAssign starting values of parameters6.6. Use the function minimize to minimize the Use the function minimize to minimize the EE
function (deviations).function (deviations).
Square-mean approximation in MathCAD
Advantageous of Advantageous of minimizeminimize function: function: simplesimple explicitexplicit suitable for any approximating functionsuitable for any approximating function ccan be used in optimisation problem an be used in optimisation problem
solvingsolving
Other MathCAD tools for approximation
genfit
Syntax:Syntax:cc:=genfit(:=genfit(X, YX, Y, , cc0, 0, FF)) XX – – vector of vector of independent values from data set independent values from data set YY - - vector ofvector of dependent values from data set dependent values from data set cc0 – starting vector of searched parameters0 – starting vector of searched parameters F F – vector function of independent variable and – vector function of independent variable and
vector c, consists of approximating function and its vector c, consists of approximating function and its derivatives on parametersderivatives on parameters
cc - vector of searched parameters - vector of searched parameters
regress Approximation by polynomial functionApproximation by polynomial function
Syntax: Syntax: ZZ:= regress(:= regress(X, Y, sX, Y, s) ) XX – vector of independent values from data – vector of independent values from data
setset YY - vector of dependent values from data set - vector of dependent values from data set ss – polynomial degree – polynomial degree ZZ – result: vector, – result: vector, ss+1 last elements are +1 last elements are
parameters of polynomial (starting from parameters of polynomial (starting from xx00 parameter)parameter)
Linear, cubic, polynomial - splineinterpolating approximation
Approximation by Approximation by linear (cubic etc.)linear (cubic etc.) spline spline function function Syntax: Syntax: ZZ:=lspline(:=lspline(X, YX, Y)) (cspline, pspline)(cspline, pspline)
XX – vector of independent values from data set – vector of independent values from data set YY - vector of dependent values from data set - vector of dependent values from data set Data in set has to be sorted! Manually or by useData in set has to be sorted! Manually or by use
of of function csort: function csort: WW:=csort(:=csort(W,iW,i), ), WW – matrix of – matrix of data, data, ii – nr of ordering column – nr of ordering column
ZZ – result: vector of parameters of cubic spline – result: vector of parameters of cubic spline functionfunction
Can be derivate
Can be integrate
Interpreting function Operates on vectors obtained from regress and spline Operates on vectors obtained from regress and spline
family functionsfamily functions Building the continuous approximating function on Building the continuous approximating function on
the base of determined parametersthe base of determined parameters Syntax: Syntax: FF((xx):=interp():=interp(Z, X, Y, xZ, X, Y, x) )
ZZ – vector given by approximating function – vector given by approximating function XX – vector of independent values from data set – vector of independent values from data set YY - vector of dependent values from data set - vector of dependent values from data set xx – independent – independent variable (local)variable (local)
Interpreting function is implicit but can be derivateInterpreting function is implicit but can be derivatedd and integrateand integratedd
MathCAD
The animationThe animation
Animation
EnhanceEnhancess understanding of numerical understanding of numerical outputoutput
Animations shows time dependences in real Animations shows time dependences in real time, time, as well as speeded upas well as speeded up or slowed or slowed down.down.
Make impression on viewersMake impression on viewers
Animation
Base of animation is variable called:Base of animation is variable called:
FRAMEFRAME Built inBuilt in, , integer typeinteger type Definition only in dialog box of animationDefinition only in dialog box of animation Parameters are: Parameters are:
starting valuestarting valueending valueending valueframe rate (frames per seconds)frame rate (frames per seconds)
Creating animation Solve a problem Solve a problem (e.g. (e.g. create functioncreate function)) Assign counting variable to FRAMEAssign counting variable to FRAME Define a variable representing each state of solution Define a variable representing each state of solution
assigned to counting variableassigned to counting variable Create plot to animateCreate plot to animate Select plot areaSelect plot area DDisplay animate dialog box and isplay animate dialog box and sselect plot elect plot Define FRAME variable parametersDefine FRAME variable parameters Choose format of compression for animation Choose format of compression for animation
recording.recording. Press Animate button. Press Animate button.