Scilab Bag Of Tricks - Claymore

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will clear all global variables. 2.5.3. Clearing Variables Chapter 2. Pitfalls During everyday programming it is not necessary to explicitely remove variables from the work space. All local variables of a function die on exit from that function anyhow, and the variables in the global name space usually do not need a special treatment. However, there are conditions under which it is preferable to completely wipe out a variable. This happens if one needs to avoid a pollution of the name space e.g. while working with the list of all variables, who(’local’). The correct command to kill the non-global variable v is clear v Note that there are no parentheses. The assignment v = [] sets v to the empty matrix. It does not remove the variable from the workspace. Global variables are cleared with the clearglobal function, whose syntax is the same as clear’s syntax. There is no need to worry if you do not understand how and why to kill a variable. This feature is only needed in very rare occasions. 28
Chapter 3. Programming Style The one and only general guideline to good programming style is: “Make it clear!” And one might extend that to Make it clear – first of all to you, and then to the poor persons that take over your project (after you have been fired, because of writing illegible code). Every possible style feature of the language should be used to express the meaning of the code more clearly. 3.1. Spacing and Formatting Although often underestimated, the format, i.e. the visual layout of the source code itself can greatly help in the understanding of the actions described therein. 3.1.1. Intra-Expression Spacing We often run into code like this x=a*c+(x-y)^2*b This is not bad, especially when typed at the command line for one-time use. However, the expression is not as clear as it could be. It can easily be improved by making the precedence levels (see also Section 4.2) of the operators stand out, as e.g. x = a*c + b*(x-y)^2 Now, the assignment is intuitively clear at first glance. We use the word “intuitive” here alert the reader of the consequences of incorrectly formatting an expression. Then our intuition will mislead us, as in x = a * c+(x-y)^2*b Ouch! This expression is evaluated differently from what it is telling us. We should call it a liar. See also Section 2.2 for the influence of whitespace on the evaluation of dotted operators. 3.1.2. Line Breaking Breaking a long expression into lines can improve its readability dramatically. It is particularly recommended for matrix definitions with the square bracket operator. See also Section 2.2. 29
Page 1: Scilab Bag Of Tricks The Scilab-2.5
Page 4 and 5: Revision History Revision 0.14 2001
Page 6 and 7: 4.4.3. Bulletproof Functions.......
Page 8 and 9: 6.6.1.3. Lhs ......................
Page 11 and 12: List of Tables 4-1. List of all ope
Page 13 and 14: Preface Often we encounter technica
Page 15 and 16: data checksum sci-bot.ps.bz2 sci-bo
Page 17 and 18: Chapter 1. Introduction “I have r
Page 19 and 20: Chapter 2. Common Pitfalls The nice
Page 21 and 22: ->m1 = [1+%i -1+%i; -1+%i 1-%i] m1
Page 23 and 24: 2.5. Variable Lifetime And Scoping
Page 25 and 26: } void first_local(void) { int x =
Page 27: ->useglobal() !-error 4 undefined v
Page 31 and 32: 3.2. Indentation Chapter 3. Style H
Page 33 and 34: 3.4. Choice Of Control Structures C
Page 35 and 36: %f %f] then s = dense’ else s =
Page 37 and 38: Chapter 4. Unknown Spots In this ch
Page 39 and 40: Chapter 4. Unknown Spots Modern lan
Page 41 and 42: Variable type Code string optype Co
Page 43 and 44: Operator Code Note >= 4 greater-or-
Page 45 and 46: names which are not already used by
Page 47 and 48: f = frac(2, 3); g = frac(1, 3); h =
Page 49 and 50: ~~~~~~~~~~~~~~~%t returns F. Chapte
Page 51 and 52: Chapter 4. Unknown Spots The parent
Page 53 and 54: [nl, nr] = argn(0); ➊ if nr ~= 1
Page 55 and 56: ->fun(2, 3, 4) ans = 9. Chapter 4.
Page 57 and 58: f = 0.5 * norm(diff)^2; g = grad’
Page 59 and 60: 4.5. Libraries of sci-functions Cha
Page 61 and 62: lvandijk@hydra:~/hsc/scilab/src/min
Page 63 and 64: minilib 4.5.2. genlib Chapter 4. Un
Page 65 and 66: Chapter 4. Unknown Spots Starting s
Page 67 and 68: Chapter 4. Unknown Spots What one m
Page 69 and 70: Chapter 5. Performance Scilab—The
Page 71 and 72: end Chapter 5. Performance The seco
Page 73 and 74: 5.1.2.1. $-Constant Chapter 5. Perf
Page 75 and 76: 5.1.3.1.2. linspace The syntax of l
Page 77 and 78: Chapter 5. Performance mat(i, i) =
Page 79 and 80:
! 1. 3. 4. 5. ! ->a(index) ans = !
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5.1.3.3.3. and, or Chapter 5. Perfo
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->mat1 = [11 12; 21 22; 31 32] mat1
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5.1.3.3.8. matrix A (hyper-)matrix
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Chapter 5. Performance So what is w
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[n, m] = size(a) b = zeros(n, m) if
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Figure 5-1. Benchmark results for t
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double precision function fals(x) d
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{ } return 2.0 / (2.0 + sin(10.0 *
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use Interfaces.Fortran; with Ada.Nu
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Chapter 5. Performance Our experien
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Chapter 6. Scilab Core Aerosmith vi
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pAda C type TypeString is String (1
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procedure dgemm (OrientationA : in
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Chapter 6. Scilab Core * PARAMETERS
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Chapter 6. Scilab Core type FloatVe
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external dcopy, dgeqrf, dorgqr, zge
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* get ready to exit if (lhs .ge. 1)
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6.3.2. Functionals Chapter 6. Scila
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character*6 namef - Name of the rou
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* catch all other errors write(errs
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}; C2F(intgen), C2F(intgk), C2F(int
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end 6.4.3. Messages limit = limit /
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Example See also Chapter 6. Scilab
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Example See also Chapter 6. Scilab
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6.5.2.5. getscalar Synopsis functio
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Example array (Positive range ) of
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6.6.1. Query Chapter 6. Scilab Core
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6.6.1.3. Lhs Synopsis function Lhs
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Chapter 6. Scilab Core stk(idx1) an
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Description Example FIXME: Write it
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} See also /* compute Vandermonde m
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See also FreePtr 6.6.3.3. FreePtr S
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Description Example Chapter 6. Scil
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6.6.4.5. SciString Synopsis procedu
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Chapter 7. Further Information We a
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scilex binaries Code optimized for
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Lmi.ps - LMI-Optimization Toolbox F
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Chapter 8. Complete Examples Welcom
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end q0 = q0 * q case 16 then // tli
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function b = %s_2_frac(s, f) assert
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= %frac_m_s(f, s) function r = %fra
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end warning(’could not achieve pr
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eps = 10^(-d); fl = frac2float( flo
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delta = [r(:, 2); r($, 2)] - [r(1,
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operator ’==’ is used. // // RE
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end 8.4. whatis.sci end if jcurs
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deff(’b = hm_isstring(hm)’, ..
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end 8.5. Auto-Determination of Prec
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Chapter 8. Complete Examples // wit
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Chapter 8. Complete Examples row =
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8.7. quadpack.sci Chapter 8. Comple
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Appendix A. GNU Free Documentation
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3. COPYING IN QUANTITY Appendix A.
Page 187 and 188:
Appendix A. GNU Free Documentation
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Appendix B. GNU General Public Lice
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2. MODIFICATIONS Appendix B. GNU Ge
Page 193 and 194:
6. REDISTRIBUTION Appendix B. GNU G
Page 195 and 196:
Appendix B. GNU General Public Lice
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Bibliography [Cameron:1996] Debra C
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Index Symbols $ constant, 73 & (See
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E Lmi.ps, 151 Manual.ps, 151 Metane
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H I J getf (See function, getf) Gli
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P [ ; ], 42 \, 42 \., 42 ^, 42 |, 4
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native functions, 108 functionals,
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