Maintainability SEI Calculation uses log2 instead of ln

[wienans]

Branch 2.x

multimetric/multimetric/cls/calc/maintenance.py

Lines 74 to 79 in 8daf11b

	try:
	res = 171.0 - (5.2 * math.log2(metrics["halstead_volume"]))
	res -= 0.23 * metrics["cyclomatic_complexity"]
	res -= 16.2 * math.log2(metrics["loc"])
	res += 50.0 * abs(math.sin(math.sqrt(2.4 * metrics["comment_ratio"])))
	return res

V1.3

multimetric/multimetric/cls/calc/maintenance.py

Lines 8 to 23 in 1bb8a8b

	MI_METHOD = {
	"sei": '171.0 \
	- (5.2 * math.log2(metrics["halstead_volume"])) \
	- (0.23 * metrics["cyclomatic_complexity"]) \
	- (16.2 * math.log2(metrics["loc"])) \
	+ (50.0 * math.sin(math.sqrt(2.4 * metrics["comment_ratio"])))',
	"classic": '171.0 \
	- (5.2 * math.log(metrics["halstead_volume"])) \
	- (0.23 * metrics["cyclomatic_complexity"]) \
	- (16.2 * math.log(metrics["loc"]))',
	"microsoft": 'max(0, \
	171.0 \
	- (5.2 * math.log(metrics["halstead_volume"])) \
	- (0.23 * metrics["cyclomatic_complexity"]), \
	- (16.2 * math.log(metrics["loc"]) * 100.0 / 171.0))'
	}

Hey i found a issue that the SEI maintainiblity calculation uses log base 2 instead of ln like discribed in the reference given https://insights.sei.cmu.edu/documents/1625/1997_002_001_16523.pdf page 232

Appart from that the documentation of classic method does not match the calculation

multimetric/multimetric/cls/calc/maintenance.py

Line 157 in 8daf11b

171 - 5.2 x ln(aveVol) - 0.23 x aveV(g’) - 16.2 x ln(aveLoC) + (50 x sin(sqrt(2.46 x perCM)))

[priv-kweihmann]

Patches welcome!!!!

[wienans]

@priv-kweihmann please see PullRequest #82

[priv-kweihmann]

PR merged, I guess we can close the ticket now

[wienans]

Thanks. Currently working on a additional PR about the radon calculation. And as I tried to implement it noticed that Comment percent is not 0-1 which is expected. This might be problematic for sei too might do changes to sei too will try to verify calculations externally