Help/Other Topics/Tracing Processes.html

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  36 <p class="p1"><b>Tracing processes in SC</b></p>
  37 <p class="p2"><br></p>
  38 <p class="p3">What goes on in a running system? In SC, various methods help to get information about processes on different levels: server side and client side (in sclang).</p>
  39 <p class="p2"><br></p>
  40 <p class="p4"><span class="s1">related:<span class="Apple-converted-space">  </span><a href="../Language/Debugging-tips.html"><span class="s2">Debugging-tips</span></a></span></p>
  41 <p class="p2"><br></p>
  42 <p class="p5"><b>Tracing sclang processes:</b></p>
  43 <p class="p6"><br></p>
  44 <p class="p3">In order to know more about objects as they are created by processes like tasks or even simply by evaluating a bit of code, one can insert messages like postln and postcs anywhere in the code.</p>
  45 <p class="p6"><br></p>
  46 <p class="p7">// calculating the sum of n subsequent squares</p>
  47 <p class="p8">(</p>
  48 <p class="p8"><span class="s3">var</span> n = 8, x = 0;</p>
  49 <p class="p8">(1..n).do { <span class="s3">|num|</span> x = x + num.squared };</p>
  50 <p class="p8">x</p>
  51 <p class="p8">)</p>
  52 <p class="p9"><br></p>
  53 <p class="p7">// what happens while we are doing this?</p>
  54 <p class="p8">(</p>
  55 <p class="p8"><span class="s3">var</span> n = 8, x = 0;</p>
  56 <p class="p8">(1..n).do { <span class="s3">|num|</span> x = x + num.squared.postln; };</p>
  57 <p class="p8">x</p>
  58 <p class="p8">)</p>
  59 <p class="p9"><br></p>
  60 <p class="p7">// or more in detail:</p>
  61 <p class="p8">(</p>
  62 <p class="p8"><span class="s3">var</span> n = 8, x = 0;</p>
  63 <p class="p8">(1..n).do { <span class="s3">|num|</span> [<span class="s4">\before</span>, x].postln; x = x + num.squared; [<span class="s4">\after</span>, x].postln;};</p>
  64 <p class="p8">x</p>
  65 <p class="p8">)</p>
  66 <p class="p9"><br></p>
  67 <p class="p9"><br></p>
  68 <p class="p7">// when posting several values, some more verbose posts can be useful.</p>
  69 <p class="p7">// postf formats a string and inserts values for %-characters.</p>
  70 <p class="p7">// here separate statements are needed.</p>
  71 <p class="p9"><br></p>
  72 <p class="p8">(</p>
  73 <p class="p8"><span class="s3">var</span> n = 8, x = 0;</p>
  74 <p class="p8">(1..n).do { <span class="s3">|num|</span> x = x + num.squared; <span class="s5">"num: % num-squared: % new x: %\n"</span>.postf(num, num.squared, x) };</p>
  75 <p class="p8">x</p>
  76 <p class="p8">)<span class="Apple-converted-space"> </span></p>
  77 <p class="p9"><br></p>
  78 <p class="p7">// in some cases, postln will only post part of the data, or a simplified</p>
  79 <p class="p7">// representation.</p>
  80 <p class="p9"><br></p>
  81 <p class="p7">// n times 200 random numbers</p>
  82 <p class="p7">// will just add ... etc ... after 123</p>
  83 <p class="p8">(</p>
  84 <p class="p8"><span class="s3">var</span> n = 3;</p>
  85 <p class="p8">(1..n).do { <span class="s3">|num|</span> { 1000.rand }.dup(200).postln };</p>
  86 <p class="p8">)</p>
  87 <p class="p9"><br></p>
  88 <p class="p7">// posts the compile string, i.e. the code needed to recreate the receiver (here the array)</p>
  89 <p class="p8">(</p>
  90 <p class="p8"><span class="s3">var</span> n = 3;</p>
  91 <p class="p8">(1..n).do { <span class="s3">|num|</span> { num.rand }.dup(200).postcs };</p>
  92 <p class="p8">)</p>
  93 <p class="p9"><br></p>
  94 <p class="p9"><br></p>
  95 <p class="p7">// in streams, tasks and routines, this works just as well:</p>
  96 <p class="p8">(</p>
  97 <p class="p8">fork {<span class="Apple-tab-span">       </span></p>
  98 <p class="p8"><span class="Apple-tab-span">     </span><span class="s3">var</span> n = 14;</p>
  99 <p class="p8"><span class="Apple-tab-span">     </span>(1..n).do { <span class="s3">|num|</span><span class="Apple-converted-space"> </span></p>
 100 <p class="p8"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>{ num.rand }.dup(200).postcs;</p>
 101 <p class="p8"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>1.wait;</p>
 102 <p class="p8"><span class="Apple-tab-span">     </span>};</p>
 103 <p class="p8">}</p>
 104 <p class="p8">)</p>
 105 <p class="p9"><br></p>
 106 <p class="p8">(</p>
 107 <p class="p8">fork {<span class="Apple-tab-span">       </span></p>
 108 <p class="p8"><span class="Apple-tab-span">     </span><span class="s3">var</span> str = <span class="s3">Routine</span> { <span class="s3">|in|</span> 10.do { in = in.rand.yield } };</p>
 109 <p class="p8"><span class="Apple-tab-span">     </span>12.0.do { <span class="s3">|i|</span></p>
 110 <p class="p8"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>str.next(i).postln;</p>
 111 <p class="p8"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>0.5.wait;</p>
 112 <p class="p8"><span class="Apple-tab-span">     </span>};</p>
 113 <p class="p8">}</p>
 114 <p class="p8">)</p>
 115 <p class="p9"><br></p>
 116 <p class="p9"><br></p>
 117 <p class="p7">// for creating a pattern that once it is used posts its values,</p>
 118 <p class="p7">// the message trace can be used (in returns a Ptrace)</p>
 119 <p class="p9"><br></p>
 120 <p class="p8">a = <span class="s3">Pseq</span>([1, 4, 1, <span class="s3">Pwhite</span>(0, 6, 3), 100, 39], <span class="s3">inf</span>).trace(prefix: <span class="s5">"value: "</span>);</p>
 121 <p class="p8">b = a.asStream;</p>
 122 <p class="p8">b.next;</p>
 123 <p class="p8">b.next;</p>
 124 <p class="p8">b.next;</p>
 125 <p class="p8">b.next;</p>
 126 <p class="p9"><br></p>
 127 <p class="p7">// in a running stream:</p>
 128 <p class="p8">(</p>
 129 <p class="p10">Pbind<span class="s1">(</span></p>
 130 <p class="p8"><span class="Apple-tab-span">     </span><span class="s4">\degree</span>, <span class="s3">Pseq</span>([1, 4, 1, <span class="s3">Pwhite</span>(0, 6, 3), 100, 39], <span class="s3">inf</span>).trace(prefix: <span class="s5">"value: "</span>),</p>
 131 <p class="p8"><span class="Apple-tab-span">     </span><span class="s4">\dur</span>, 0.2</p>
 132 <p class="p8">).play</p>
 133 <p class="p8">);</p>
 134 <p class="p9"><br></p>
 135 <p class="p7">// post only a slot of the events</p>
 136 <p class="p8">(</p>
 137 <p class="p10">Pbind<span class="s1">(</span></p>
 138 <p class="p8"><span class="Apple-tab-span">     </span><span class="s4">\degree</span>, <span class="s3">Pseq</span>([1, 4, 1, <span class="s3">Pwhite</span>(0, 6, 3), 100, 39], <span class="s3">inf</span>),</p>
 139 <p class="p8"><span class="Apple-tab-span">     </span><span class="s4">\dur</span>, 0.2</p>
 140 <p class="p8">).trace(<span class="s4">\degree</span>).play</p>
 141 <p class="p8">);</p>
 142 <p class="p6"><br></p>
 143 <p class="p7">// several slots at once:</p>
 144 <p class="p8">(</p>
 145 <p class="p10">Pbind<span class="s1">(</span></p>
 146 <p class="p8"><span class="Apple-tab-span">     </span><span class="s4">\degree</span>, <span class="s3">Pseq</span>([1, 4, 1, <span class="s3">Pwhite</span>(0, 6, 3), 100, 39], <span class="s3">inf</span>),</p>
 147 <p class="p8"><span class="Apple-tab-span">     </span><span class="s4">\dur</span>, <span class="s3">Pwhite</span>(0.2, 0.4, <span class="s3">inf</span>)</p>
 148 <p class="p8">).trace([<span class="s4">\degree</span>, <span class="s4">\dur</span>], prefix: [<span class="s5">"degree "</span>, <span class="s5">"dur "</span>]).play</p>
 149 <p class="p8">);</p>
 150 <p class="p6"><br></p>
 151 <p class="p6"><br></p>
 152 <p class="p2"><br></p>
 153 <p class="p5"><b>Tracing server processes:</b></p>
 154 <p class="p6"><br></p>
 155 <p class="p3">Using postln or post on a UGen will only return the UGen, but not the values it produces in a running synth. The poll message creates a Poll UGen which posts at regular intervals when given a time value or as a response to a trigger (see <a href="../UGens/Triggers/Poll.html"><span class="s6">Poll</span></a> helpfile)</p>
 156 <p class="p6"><br></p>
 157 <p class="p7">// postln returns only the UGen itself (a MulAdd here)</p>
 158 <p class="p8">{ <span class="s3">SinOsc</span>.ar(<span class="s3">SinOsc</span>.kr(0.2, 0, 300, 400).postln) * 0.1 }.play;</p>
 159 <p class="p9"><br></p>
 160 <p class="p7">// poll traces the values</p>
 161 <p class="p8">{ <span class="s3">SinOsc</span>.ar(<span class="s3">SinOsc</span>.kr(0.2, 0, 300, 400).poll) * 0.1 }.play;</p>
 162 <p class="p9"><br></p>
 163 <p class="p7">// using a label:</p>
 164 <p class="p8">{ <span class="s3">SinOsc</span>.ar(<span class="s3">SinOsc</span>.kr(0.2, 0, 300, 400).poll(label: <span class="s5">"freq"</span>)) * 0.1 }.play;</p>
 165 <p class="p6"><br></p>
 166 <p class="p6"><br></p>
 167 <p class="p3">For <b>demand ugens</b>, poll does not work - these ugens are called by a Demand or Duty Ugen at certain intervals. The message dpoll creates a Dpoll ugen that posts when they are called (see <a href="../UGens/Synth control/Demand Rate/Dpoll.html"><span class="s6">Dpoll</span></a> helpfile)</p>
 168 <p class="p6"><br></p>
 169 <p class="p9"><br></p>
 170 <p class="p8">{ <span class="s3">SinOsc</span>.ar(<span class="s3">Duty</span>.kr(0.5, 0, (<span class="s3">Dseries</span>(0, 1, <span class="s3">inf</span>) * 200 + 300).dpoll)) * 0.1 }.play;</p>
 171 <p class="p9"><br></p>
 172 <p class="p8">{ <span class="s3">SinOsc</span>.ar(<span class="s3">Duty</span>.kr(0.5, 0, (<span class="s3">Dseries</span>(0, 1, <span class="s3">inf</span>) * 200 + 300).dpoll(label: <span class="s5">"freq"</span>))) * 0.1 }.play;</p>
 173 <p class="p9"><br></p>
 174 <p class="p6"><br></p>
 175 <p class="p3">When using the internal server (see <a href="../ServerArchitecture/Server.html"><span class="s7">Server</span></a> help), the <b>scope</b> window can give valuable information about the ongoing sound (see <a href="../GUI/Main-GUI/Stethoscope.html"><span class="s7">Stethoscope</span></a> help):</p>
 176 <p class="p6"><br></p>
 177 <p class="p11">// must use internal server</p>
 178 <p class="p8">s = <span class="s8">Server</span>.internal.boot;</p>
 179 <p class="p8">{ <span class="s9">SinOsc</span>.ar(<span class="s9">SinOsc</span>.kr(0.2, 0, 300, 400)) * 0.1 }.scope;</p>
 180 <p class="p9"><br></p>
 181 <p class="p3">A <a href="../GUI/Main-GUI/FreqScope.html"><span class="s10">FreqScope</span></a> window can be used for observing the spectrum of the output:</p>
 182 <p class="p9"><br></p>
 183 <p class="p11">// must use internal server</p>
 184 <p class="p8"><span class="s3">Server</span>.default = s = <span class="s3">Server</span>.internal.boot;</p>
 185 <p class="p9"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span></p>
 186 <p class="p11">// create a new analyzer</p>
 187 <p class="p12">FreqScope<span class="s1">.new;</span></p>
 188 <p class="p9"><br></p>
 189 <p class="p8">{ <span class="s9">SinOsc</span>.ar(<span class="s9">SinOsc</span>.ar(0.2, 0, 3000, 4000)) * 0.1 }.play;</p>
 190 <p class="p8">{ <span class="s9">SinOsc</span>.ar(<span class="s9">SinOsc</span>.ar((1..4) * 0.02, 0, 3000, 4000)).sum * 0.1 }.play;</p>
 191 <p class="p9"><br></p>
 192 <p class="p9"><br></p>
 193 <p class="p9"><br></p>
 194 <p class="p9"><br></p>
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