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Proektsoftbg / Calcpad

Free and open source software for mathematical and engineering calculations.
https://calcpad.eu
MIT License
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Some missing units #252

Open FEA-eng opened 5 months ago

FEA-eng commented 5 months ago

Hi,

I've noticed that the following units are not available in Calcpad and would be nice to have:

Proektsoftbg commented 5 months ago

Hi! Thank you for your suggestions.

Some of them we already have. Week is "w" and year is "y". I doubted about month before because different months have different number of days - 28(29), 30 and 31. Probably 30 days would be OK, but there is some ambiguity.

And what is "b" an "B"?

FEA-eng commented 5 months ago

Some of them we already have. Week is "w" and year is "y".

Right, they aren't listed on the main page (https://github.com/Proektsoftbg/Calcpad) so I thought they aren't available.

I doubted about month before because different months have different number of days - 28(29), 30 and 31. Probably 30 days would be OK, but there is some ambiguity.

I've seen the value of 30.4368499 days used in some cases. Like in SMath or Google if you search for "month to days".

And what is "b" an "B"?

b - bit, B - byte

Proektsoftbg commented 5 months ago

OK. Thank you. Probably I have forgotten to add "w" and "y" to this readme at the time they were implemented. I will update it accordingly,

About SMath, probably they defined month as average = year/12.

image

In this respect, probably we have to reconsider the unit for years "y" in Calcpad. Now it is 365 days. In SMath, it is 365.2425 days, which is according to the Gregorian calendar: https://en.wikipedia.org/wiki/Leap_year

However, in MathCAD, it is 365.24219878125 days, which is probably something like an exact "tropical" year duration: https://en.wikipedia.org/wiki/Tropical_year

image

There is also "astronomical" year, which is defined as 365.25 days by convention: https://multiverse.ssl.berkeley.edu/Portals/0/CalendarInTheSky/Resources/Presentations/HowLongIsAYear.pdf?ver=Wt-kX9xEaM0fZve8OXxBfg%3d%3d

To be honest, as a structural engineer I am getting confused by having so many "years". The question is what is the most appropriate to assume in Calcpad. The SMath approach seems to be more practical and simpler for everyday engineering calcs.

FEA-eng commented 5 months ago

Even more definitions here: https://www.physicsforums.com/insights/measuring-how-many-days-are-in-a-year/

I think that I would choose the approach used in SMath too.

Proektsoftbg commented 5 months ago

OK. Thank you! I will make the required changes.