Yade

explain returns of yade.utils.psd

Asked by Mahdeyeh

Dear all,
I have a question in returns of yade.utils.psd in simulating clumps spherical particles.
I have modeled 3000 particles, I mean I have 3000 clumps.
Particle size distribution for them is 8 cm to 100 cm.
Around of particles in yade is facet.

When I want psd with yade.utils.psd(mass=True), it gives me these:

(array([0.0026, 0.055 , 0.1074, 0.1598, 0.2122, 0.2646]),
 array([0. , 0.06952433, 0.30856434, 0.48348666, 0.88043175,
        1. ]),
 array([ 0. , 1259.17422258, 5588.49372188, 8756.56001507,
        15945.74175232, 18111.27531567]))

I read [1] , but actually I could not understand what is these arrays! if first array is sizes of my particles so why it is until 26 cm?

Many thanks for your help.
Best regards,

[1] https://yade-dem.org/doc/yade.utils.html?highlight=yade%20utils%20psd#yade.utils.psd

ubuntu : 18.04
yade 2018.02b

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Jan Stránský
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Best Jan Stránský (honzik) said : 		#1

Hello,

> ... why it is until 26 cm?

difficult to say without actual example, sizes ...
please provide a MWE [2]

Also note that yade.utils.psd counts only with spheres as such, regardless clumps [3].

Cheers
Jan

[2] https://www.yade-dem.org/wiki/Howtoask
[3] https://gitlab.com/yade-dev/trunk/-/blob/master/py/utils.py#L880

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Jérôme Duriez (jduriez) said : 		#2

1st array is a size array. 2nd array in a proportion array, with respect to the sizes in 1st array. 3rd array is passing mass, with respect to sizes of 1st array, if I remember correctly.

(And +1 on the clump remark by Jan)

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Mahdeyeh (mahdiye.sky) said : 		#3

Thank you Jan Stránský and Jérôme Duriez .

> Also note that yade.utils.psd counts only with spheres as such, regardless clumps [3].

I understand , those sizes are for spheres of my clumps not size of clumps.

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Mahdeyeh (mahdiye.sky) said : 		#4

Thanks Jan Stránský, that solved my question.

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Jan Stránský (honzik) said : 		#5

If this is the issue, you can "copy-paste" the function code to your own function adjusted for clumps.
E.g. isinstance(b.shape,Sphere) -> b.isClump, b.shape.radius -> yourFunctionDeterminingClumpSize(b), etc.
Cheers
Jan

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Mahdeyeh (mahdiye.sky) said : 		#6

thanks a lot for your suggestion.