Longer computation time for HB[+] Analysis Grid

C.Bech · August 6, 2019, 9:20am

Hi all
I am wondering:

Why is it that generating a lot of test points in the analysisGrid component from HB [+] takes a lot longer time to compute than the similar HB legacy component GenMesh?
This is especially notable when connecting the analysisGrid to the HoneybeePlus_Annual Daylight Recipe module.

Best regards,
Christian

ComputationTime_Honeybee_Grid.gh (468.0 KB)

minggangyin · August 7, 2019, 2:51am

@C.Bech Maybe the grid-size is set to too small. HB [+] is default using Meters for Units.If your model is using MilliMeters, you should scale it.

C.Bech · August 7, 2019, 1:09pm

It is not the case here - the grid is adjusted so it is the same spacing.

minggangyin · August 8, 2019, 1:30am

@C.Bech You should post some screenshot for this question. If you can upload the rhino model and grasshooper definition, it will be nice for this discussion.

C.Bech · August 8, 2019, 7:46am

@minggangyin
You are right I uploaded the GH file as well as an attached image. This test is made with a very simple surface of 20x20 meters. A HB [+] computation time of 2 minutes might not seem as much but a relative comparison to Honeybee Legacy show quite a significant difference in computation time.

minggangyin · August 8, 2019, 7:56am

@C.Bech Sorry, I can not see any images. Please check it.

Frank_Gergaud · August 8, 2019, 7:57am

Hi Christian,

I’ve found out the same problem. It’s very slow to create a daylight grid. It’s actually the same with creating HB surfaces.

Frank

mostapha · August 11, 2019, 3:12am

This is a known issue and is going to be addressed with AnalysisGridLite which is already implemented in source code but hasn’t been ported to the Grasshopper plugin:

github.com

ladybug-tools/honeybee/blob/master/honeybee/radiance/analysisgridlite.py

"""Honeybee PointGroup and TestPointGroup."""
from __future__ import division
from ..utilcol import random_name
from ..futil import write_to_file_by_name
from .analysispointlite import AnalysisPointLite as AnalysisPoint

import os
try:
    from itertools import izip as zip
except:
    # python 3
    pass

class AnalysisGridLite(object):
    """A grid of analysis points.

    Attributes:
        analysis_points: A collection of analysis points.
    """

This file has been truncated. show original

Here is the longer explanation:

In the current implementation AnalysisPoint carries all the results for that point. This means you can call methods like AnalysisPoint.annual_metrics directly from the point which is handy and in my opinion how it should be. The implementation works just fine in Python - but it becomes very slow in Grasshopper. I was unable to figure out what exactly happens but for any reason it became a major performance issue in Honeybee[+].

To address this issue we have broken down these two responsibilities into two separate classes. AnalysisPointLite only carries the position and direction of the point and the results will be loaded to a Sqlite database. There is a ResultCollection class that handles the calls to database so we can get a high performance without overloading Grasshopper.

Now you are probably thinking why it has not made its way to Grasshopper if the issue has been solved. The answer is that we are overhauling the way the studies are undertaken with Honeybee[+]. See:

this issue: https://github.com/ladybug-tools/honeybee/issues/266
honeybee-radiance repository: https://github.com/ladybug-tools/honeybee-radiance
honeybee-radiance-folder repository: https://github.com/ladybug-tools/honeybee-radiance-folder
and honeybee-radiance-workflow repository: https://github.com/ladybug-tools/honeybee-radiance-workflow

Hope it helps.

C.Bech · August 12, 2019, 8:08am

@mostapha

Thanks a lot for the elaborated explanation of the observation, and I think you are right and have found a good compromise by dividing the component into two separate classes.

Overhauling Honeybee[+] must be hard work - wish you good luck, and thank you for your the great work so far.

Best regards,
Christian

Frank_Gergaud · August 12, 2019, 9:07am

Hi Mostapha,

Really nice to get a full explanation about this issue, now it makes a lot of sense.

Thanks for your great work so far

Frank