Approximate equality: Difference between revisions

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=={{header|Phix}}==
=={{header|Phix}}==
Traditionally I have always just used sprintf() to compare floating point atoms in phix.<br>
Traditionally I have always just used sprintf() to compare floating point atoms in phix.<br>
This task (imo) is trying to make a general-purpose routine out of code (ie bool eq) which is best tailored for each and every specific task.<br>
This task (imo) is trying to make a general-purpose routine out of code which is best tailored for each and every specific task.<br>
It proved much harder to get decent-looking output than perform the tests, hence I allowed both the compare (cfmt) and display (dfmt) formats to be overridden.<br>
It proved much harder to get decent-looking output than perform the tests, hence I allowed both the compare (cfmt) and display (dfmt) formats to be overridden.<br>
I got a different result for test 4 to everyone else, but simply setting the cfmt to "%.8f" got it the NOT.<br>
I got a different result for test 4 to everyone else, but simply setting the cfmt to "%.10f" got it the NOT.<br>
Likewise something similar for the trickier/ambiguous test 5, and both now show how to get either a true or false result.
Likewise something similar for the trickier/ambiguous test 5, and both now show how to get either a true or false result.
<!--<lang Phix>(phixonline)-->
<lang Phix>procedure test(atom a,b, string dfmt="%g", cfmt="%g")
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
bool eq = sprintf(cfmt,a)==sprintf(cfmt,b)
<span style="color: #008080;">procedure</span> <span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">a</span><span style="color: #0000FF;">,</span><span style="color: #000000;">b</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">string</span> <span style="color: #000000;">dfmt</span><span style="color: #0000FF;">=</span><span style="color: #008000;">"%g"</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">cfmt</span><span style="color: #0000FF;">=</span><span style="color: #008000;">"%g"</span><span style="color: #0000FF;">)</span>
string eqs = iff(eq?"":"NOT "),
<span style="color: #004080;">string</span> <span style="color: #000000;">ca</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">sprintf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cfmt</span><span style="color: #0000FF;">,</span><span style="color: #000000;">a</span><span style="color: #0000FF;">),</span>
sa = sprintf(dfmt,a),
<span style="color: #000000;">cb</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">sprintf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cfmt</span><span style="color: #0000FF;">,</span><span style="color: #000000;">b</span><span style="color: #0000FF;">),</span>
sb = sprintf(dfmt,b)
<span style="color: #000000;">eqs</span> <span style="color: #0000FF;">=</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">ca</span><span style="color: #0000FF;">=</span><span style="color: #000000;">cb</span><span style="color: #0000FF;">?</span><span style="color: #008000;">""</span><span style="color: #0000FF;">:</span><span style="color: #008000;">"NOT "</span><span style="color: #0000FF;">),</span>
printf(1,"%30s is %sapproximately equal to %s\n",{sa,eqs,sb})
<span style="color: #000000;">da</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">sprintf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dfmt</span><span style="color: #0000FF;">,</span><span style="color: #000000;">a</span><span style="color: #0000FF;">),</span>
end procedure
<span style="color: #000000;">db</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">sprintf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dfmt</span><span style="color: #0000FF;">,</span><span style="color: #000000;">b</span><span style="color: #0000FF;">)</span>

<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%30s is %sapproximately equal to %s\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">da</span><span style="color: #0000FF;">,</span><span style="color: #000000;">eqs</span><span style="color: #0000FF;">,</span><span style="color: #000000;">db</span><span style="color: #0000FF;">})</span>
test(100000000000000.01,100000000000000.011,"%.3f")
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
test(100.01,100.011)
test(10000000000000.001/10000.0,1000000000.0000001000,"%.10f")
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #000000;">100000000000000.01</span><span style="color: #0000FF;">,</span><span style="color: #000000;">100000000000000.011</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%.3f"</span><span style="color: #0000FF;">)</span>
test(0.001,0.0010000001,"%.8f") -- both
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #000000;">100.01</span><span style="color: #0000FF;">,</span><span style="color: #000000;">100.011</span><span style="color: #0000FF;">)</span>
test(0.001,0.0010000001,"%.8f","%.8f") -- ways
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #000000;">10000000000000.001</span><span style="color: #0000FF;">/</span><span style="color: #000000;">10000.0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1000000000.0000001000</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%.10f"</span><span style="color: #0000FF;">)</span>
test(0.000000000000000000000101,0.0,"%f") -- both
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0.001</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0.0010000001</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%.8f"</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- both</span>
test(0.000000000000000000000101,0.0,"%f","%6f") -- ways
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0.001</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0.0010000001</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%.8f"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%.10f"</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- ways</span>
test(sqrt(2)*sqrt(2),2.0)
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0.000000000000000000000101</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0.0</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%f"</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- both</span>
test(-sqrt(2)*sqrt(2),-2.0)
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0.000000000000000000000101</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0.0</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%f"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%6f"</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- ways</span>
test(3.14159265358979323846,3.14159265358979324,"%.20f")</lang>
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">sqrt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)*</span><span style="color: #7060A8;">sqrt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">2</span><span style="color: #0000FF;">),</span><span style="color: #000000;">2.0</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">test</span><span style="color: #0000FF;">(-</span><span style="color: #7060A8;">sqrt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)*</span><span style="color: #7060A8;">sqrt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">2</span><span style="color: #0000FF;">),-</span><span style="color: #000000;">2.0</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #000000;">3.14159265358979323846</span><span style="color: #0000FF;">,</span><span style="color: #000000;">3.14159265358979324</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%.20f"</span><span style="color: #0000FF;">)</span>
<!--</lang>-->
{{out}}
{{out}}
64 bit (implied by some of the accuracies specified for this task):
64 bit (implied by some of the accuracies specified for this task):
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100.01 is NOT approximately equal to 100.011
100.01 is NOT approximately equal to 100.011
1000000000.0000001001 is approximately equal to 1000000000.0000001000
1000000000.0000001001 is approximately equal to 1000000000.0000001000
0.00100000000 is approximately equal to 0.0010000001
0.0010000000000 is approximately equal to 0.001000000100
0.00100000000 is NOT approximately equal to 0.0010000001
0.0010000000000 is NOT approximately equal to 0.001000000100
0.000000000000000000000101000 is NOT approximately equal to 0.000000
0.000000000000000000000101000 is NOT approximately equal to 0.000000
0.000000000000000000000101000 is approximately equal to 0.000000
0.000000000000000000000101000 is approximately equal to 0.000000
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100.01 is NOT approximately equal to 100.011
100.01 is NOT approximately equal to 100.011
1000000000.0000002384 is approximately equal to 1000000000.0000001192
1000000000.0000002384 is approximately equal to 1000000000.0000001192
0.0010000000 is approximately equal to 0.0010000001
0.001000000000 is approximately equal to 0.001000000100
0.0010000000 is NOT approximately equal to 0.0010000001
0.001000000000 is NOT approximately equal to 0.001000000100
0.000000000000000000000101000 is NOT approximately equal to 0.000000
0.000000000000000000000101000 is NOT approximately equal to 0.000000
0.000000000000000000000101000 is approximately equal to 0.000000
0.000000000000000000000101000 is approximately equal to 0.000000
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3.1415926535897931 is approximately equal to 3.1415926535897931
3.1415926535897931 is approximately equal to 3.1415926535897931
</pre>
</pre>
Note that %.8f prints 8 digits of precision on desktop/Phix, whereas the equivalent in
Javascript, as in number.toFixed(8), prints 8 decimal places.


=={{header|Python}}==
=={{header|Python}}==
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